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bpo-40334: PEP 617 implementation: New PEG parser for CPython (GH-19503) 

Co-authored-by: Guido van Rossum <guido@python.org>
Co-authored-by: Lysandros Nikolaou <lisandrosnik@gmail.com>
This commit is contained in:
Pablo Galindo 2020-04-22 23:29:27 +01:00 committed by GitHub
parent a81849b031
commit c5fc156852
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
91 changed files with 27057 additions and 146 deletions
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45
.github/workflows/build.yml vendored
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@ -13,6 +13,7 @@ on:
- '**/*.rst'
pull_request:
branches:
- pegen
- master
- 3.8
- 3.7
@ -50,6 +51,22 @@ jobs:
build_macos:
name: 'macOS'
runs-on: macos-latest
env:
PYTHONOLDPARSER: old
steps:
- uses: actions/checkout@v1
- name: Configure CPython
run: ./configure --with-pydebug --with-openssl=/usr/local/opt/openssl --prefix=/opt/python-dev
- name: Build CPython
run: make -j4
- name: Display build info
run: make pythoninfo
- name: Tests
run: make buildbottest TESTOPTS="-j4 -uall,-cpu"
build_macos_pegen:
name: 'macOS - Pegen'
runs-on: macos-latest
steps:
- uses: actions/checkout@v1
- name: Configure CPython
@ -64,6 +81,34 @@ jobs:
build_ubuntu:
name: 'Ubuntu'
runs-on: ubuntu-latest
env:
OPENSSL_VER: 1.1.1f
PYTHONOLDPARSER: old
steps:
- uses: actions/checkout@v1
- name: Install Dependencies
run: sudo ./.github/workflows/posix-deps-apt.sh
- name: 'Restore OpenSSL build'
id: cache-openssl
uses: actions/cache@v1
with:
path: ./multissl/openssl/${{ env.OPENSSL_VER }}
key: ${{ runner.os }}-multissl-openssl-${{ env.OPENSSL_VER }}
- name: Install OpenSSL
if: steps.cache-openssl.outputs.cache-hit != 'true'
run: python3 Tools/ssl/multissltests.py --steps=library --base-directory $PWD/multissl --openssl $OPENSSL_VER --system Linux
- name: Configure CPython
run: ./configure --with-pydebug --with-openssl=$PWD/multissl/openssl/$OPENSSL_VER
- name: Build CPython
run: make -j4
- name: Display build info
run: make pythoninfo
- name: Tests
run: xvfb-run make buildbottest TESTOPTS="-j4 -uall,-cpu"
build_ubuntu_pegen:
name: 'Ubuntu - Pegen'
runs-on: ubuntu-latest
env:
OPENSSL_VER: 1.1.1f
steps:

7
.travis.yml
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@ -1,5 +1,5 @@
language: c
dist: xenial
dist: bionic
# To cache doc-building dependencies and C compiler output.
cache:
@ -22,6 +22,7 @@ env:
branches:
only:
- master
- pegen
- /^\d\.\d+$/
- buildbot-custom
@ -157,7 +158,9 @@ install:
before_script:
# -Og is much faster than -O0
- CFLAGS="${CFLAGS} -Og" ./configure --with-pydebug
- make -j4 regen-all
- eval "$(pyenv init -)"
- pyenv global 3.8
- PYTHON_FOR_REGEN=python3.8 make -j4 regen-all
- changes=`git status --porcelain`
- |
# Check for changes in regenerated files

8
Doc/using/cmdline.rst
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@ -426,6 +426,8 @@ Miscellaneous options
defines the following possible values:
* ``-X faulthandler`` to enable :mod:`faulthandler`;
* ``-X oldparser``: enable the traditional LL(1) parser. See also
:envvar:`PYTHONOLDPARSER`.
* ``-X showrefcount`` to output the total reference count and number of used
memory blocks when the program finishes or after each statement in the
interactive interpreter. This only works on debug builds.
@ -574,6 +576,12 @@ conflict.
:option:`-d` multiple times.
.. envvar:: PYTHONOLDPARSER
If this is set it is equivalent to specifying the :option:`-X`
``oldparser`` option.
.. envvar:: PYTHONINSPECT
If this is set to a non-empty string it is equivalent to specifying the

555
Grammar/python.gram Normal file
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@ -0,0 +1,555 @@
# Simplified grammar for Python
@bytecode True
@trailer '''
void *
_PyPegen_parse(Parser *p)
{
// Initialize keywords
p->keywords = reserved_keywords;
p->n_keyword_lists = n_keyword_lists;
// Run parser
void *result = NULL;
if (p->start_rule == Py_file_input) {
result = file_rule(p);
} else if (p->start_rule == Py_single_input) {
result = interactive_rule(p);
} else if (p->start_rule == Py_eval_input) {
result = eval_rule(p);
} else if (p->start_rule == Py_fstring_input) {
result = fstring_rule(p);
}
return result;
}
// The end
'''
file[mod_ty]: a=[statements] ENDMARKER { Module(a, NULL, p->arena) }
interactive[mod_ty]: a=statement_newline { Interactive(a, p->arena) }
eval[mod_ty]: a=expressions NEWLINE* ENDMARKER { Expression(a, p->arena) }
fstring[expr_ty]: star_expressions
statements[asdl_seq*]: a=statement+ { _PyPegen_seq_flatten(p, a) }
statement[asdl_seq*]: a=compound_stmt { _PyPegen_singleton_seq(p, a) } | simple_stmt
statement_newline[asdl_seq*]:
| a=compound_stmt NEWLINE { _PyPegen_singleton_seq(p, a) }
| simple_stmt
| NEWLINE { _PyPegen_singleton_seq(p, CHECK(_Py_Pass(EXTRA))) }
| ENDMARKER { _PyPegen_interactive_exit(p) }
simple_stmt[asdl_seq*]:
| a=small_stmt !';' NEWLINE { _PyPegen_singleton_seq(p, a) } # Not needed, there for speedup
| a=';'.small_stmt+ [';'] NEWLINE { a }
# NOTE: assignment MUST precede expression, else parsing a simple assignment
# will throw a SyntaxError.
small_stmt[stmt_ty] (memo):
| assignment
| e=star_expressions { _Py_Expr(e, EXTRA) }
| &'return' return_stmt
| &('import' | 'from') import_stmt
| &'raise' raise_stmt
| 'pass' { _Py_Pass(EXTRA) }
| &'del' del_stmt
| &'yield' yield_stmt
| &'assert' assert_stmt
| 'break' { _Py_Break(EXTRA) }
| 'continue' { _Py_Continue(EXTRA) }
| &'global' global_stmt
| &'nonlocal' nonlocal_stmt
compound_stmt[stmt_ty]:
| &('def' | '@' | ASYNC) function_def
| &'if' if_stmt
| &('class' | '@') class_def
| &('with' | ASYNC) with_stmt
| &('for' | ASYNC) for_stmt
| &'try' try_stmt
| &'while' while_stmt
# NOTE: annotated_rhs may start with 'yield'; yield_expr must start with 'yield'
assignment:
| a=NAME ':' b=expression c=['=' d=annotated_rhs { d }] {
_Py_AnnAssign(CHECK(_PyPegen_set_expr_context(p, a, Store)), b, c, 1, EXTRA) }
| a=('(' b=inside_paren_ann_assign_target ')' { b }
| ann_assign_subscript_attribute_target) ':' b=expression c=['=' d=annotated_rhs { d }] {
_Py_AnnAssign(a, b, c, 0, EXTRA)}
| a=(z=star_targets '=' { z })+ b=(yield_expr | star_expressions) {
_Py_Assign(a, b, NULL, EXTRA) }
| a=target b=augassign c=(yield_expr | star_expressions) {
_Py_AugAssign(a, b->kind, c, EXTRA) }
| invalid_assignment
augassign[AugOperator*]:
| '+=' {_PyPegen_augoperator(p, Add)}
| '-=' {_PyPegen_augoperator(p, Sub)}
| '*=' {_PyPegen_augoperator(p, Mult)}
| '@=' {_PyPegen_augoperator(p, MatMult)}
| '/=' {_PyPegen_augoperator(p, Div)}
| '%=' {_PyPegen_augoperator(p, Mod)}
| '&=' {_PyPegen_augoperator(p, BitAnd)}
| '|=' {_PyPegen_augoperator(p, BitOr)}
| '^=' {_PyPegen_augoperator(p, BitXor)}
| '<<=' {_PyPegen_augoperator(p, LShift)}
| '>>=' {_PyPegen_augoperator(p, RShift)}
| '**=' {_PyPegen_augoperator(p, Pow)}
| '//=' {_PyPegen_augoperator(p, FloorDiv)}
global_stmt[stmt_ty]: 'global' a=','.NAME+ {
_Py_Global(CHECK(_PyPegen_map_names_to_ids(p, a)), EXTRA) }
nonlocal_stmt[stmt_ty]: 'nonlocal' a=','.NAME+ {
_Py_Nonlocal(CHECK(_PyPegen_map_names_to_ids(p, a)), EXTRA) }
yield_stmt[stmt_ty]: y=yield_expr { _Py_Expr(y, EXTRA) }
assert_stmt[stmt_ty]: 'assert' a=expression b=[',' z=expression { z }] { _Py_Assert(a, b, EXTRA) }
del_stmt[stmt_ty]: 'del' a=del_targets { _Py_Delete(a, EXTRA) }
import_stmt[stmt_ty]: import_name | import_from
import_name[stmt_ty]: 'import' a=dotted_as_names { _Py_Import(a, EXTRA) }
# note below: the ('.' | '...') is necessary because '...' is tokenized as ELLIPSIS
import_from[stmt_ty]:
| 'from' a=('.' | '...')* b=dotted_name 'import' c=import_from_targets {
_Py_ImportFrom(b->v.Name.id, c, _PyPegen_seq_count_dots(a), EXTRA) }
| 'from' a=('.' | '...')+ 'import' b=import_from_targets {
_Py_ImportFrom(NULL, b, _PyPegen_seq_count_dots(a), EXTRA) }
import_from_targets[asdl_seq*]:
| '(' a=import_from_as_names [','] ')' { a }
| import_from_as_names
| '*' { _PyPegen_singleton_seq(p, CHECK(_PyPegen_alias_for_star(p))) }
import_from_as_names[asdl_seq*]:
| a=','.import_from_as_name+ { a }
import_from_as_name[alias_ty]:
| a=NAME b=['as' z=NAME { z }] { _Py_alias(a->v.Name.id,
(b) ? ((expr_ty) b)->v.Name.id : NULL,
p->arena) }
dotted_as_names[asdl_seq*]:
| a=','.dotted_as_name+ { a }
dotted_as_name[alias_ty]:
| a=dotted_name b=['as' z=NAME { z }] { _Py_alias(a->v.Name.id,
(b) ? ((expr_ty) b)->v.Name.id : NULL,
p->arena) }
dotted_name[expr_ty]:
| a=dotted_name '.' b=NAME { _PyPegen_join_names_with_dot(p, a, b) }
| NAME
if_stmt[stmt_ty]:
| 'if' a=named_expression ':' b=block c=elif_stmt { _Py_If(a, b, CHECK(_PyPegen_singleton_seq(p, c)), EXTRA) }
| 'if' a=named_expression ':' b=block c=[else_block] { _Py_If(a, b, c, EXTRA) }
elif_stmt[stmt_ty]:
| 'elif' a=named_expression ':' b=block c=elif_stmt { _Py_If(a, b, CHECK(_PyPegen_singleton_seq(p, c)), EXTRA) }
| 'elif' a=named_expression ':' b=block c=[else_block] { _Py_If(a, b, c, EXTRA) }
else_block[asdl_seq*]: 'else' ':' b=block { b }
while_stmt[stmt_ty]:
| 'while' a=named_expression ':' b=block c=[else_block] { _Py_While(a, b, c, EXTRA) }
for_stmt[stmt_ty]:
| is_async=[ASYNC] 'for' t=star_targets 'in' ex=star_expressions ':' b=block el=[else_block] {
(is_async ? _Py_AsyncFor : _Py_For)(t, ex, b, el, NULL, EXTRA) }
with_stmt[stmt_ty]:
| is_async=[ASYNC] 'with' '(' a=','.with_item+ ')' ':' b=block {
(is_async ? _Py_AsyncWith : _Py_With)(a, b, NULL, EXTRA) }
| is_async=[ASYNC] 'with' a=','.with_item+ ':' b=block {
(is_async ? _Py_AsyncWith : _Py_With)(a, b, NULL, EXTRA) }
with_item[withitem_ty]:
| e=expression o=['as' t=target { t }] { _Py_withitem(e, o, p->arena) }
try_stmt[stmt_ty]:
| 'try' ':' b=block f=finally_block { _Py_Try(b, NULL, NULL, f, EXTRA) }
| 'try' ':' b=block ex=except_block+ el=[else_block] f=[finally_block] { _Py_Try(b, ex, el, f, EXTRA) }
except_block[excepthandler_ty]:
| 'except' e=expression t=['as' z=target { z }] ':' b=block {
_Py_ExceptHandler(e, (t) ? ((expr_ty) t)->v.Name.id : NULL, b, EXTRA) }
| 'except' ':' b=block { _Py_ExceptHandler(NULL, NULL, b, EXTRA) }
finally_block[asdl_seq*]: 'finally' ':' a=block { a }
return_stmt[stmt_ty]:
| 'return' a=[star_expressions] { _Py_Return(a, EXTRA) }
raise_stmt[stmt_ty]:
| 'raise' a=expression b=['from' z=expression { z }] { _Py_Raise(a, b, EXTRA) }
| 'raise' { _Py_Raise(NULL, NULL, EXTRA) }
function_def[stmt_ty]:
| d=decorators f=function_def_raw { _PyPegen_function_def_decorators(p, d, f) }
| function_def_raw
function_def_raw[stmt_ty]:
| is_async=[ASYNC] 'def' n=NAME '(' params=[params] ')' a=['->' z=annotation { z }] ':' b=block {
(is_async ? _Py_AsyncFunctionDef : _Py_FunctionDef)(n->v.Name.id,
(params) ? params : CHECK(_PyPegen_empty_arguments(p)),
b, NULL, a, NULL, EXTRA) }
params[arguments_ty]:
| invalid_parameters
| parameters
parameters[arguments_ty]:
| a=slash_without_default b=[',' x=plain_names { x }] c=[',' y=names_with_default { y }] d=[',' z=[star_etc] { z }] {
_PyPegen_make_arguments(p, a, NULL, b, c, d) }
| a=slash_with_default b=[',' y=names_with_default { y }] c=[',' z=[star_etc] { z }] {
_PyPegen_make_arguments(p, NULL, a, NULL, b, c) }
| a=plain_names b=[',' y=names_with_default { y }] c=[',' z=[star_etc] { z }] {
_PyPegen_make_arguments(p, NULL, NULL, a, b, c) }
| a=names_with_default b=[',' z=[star_etc] { z }] { _PyPegen_make_arguments(p, NULL, NULL, NULL, a, b)}
| a=star_etc { _PyPegen_make_arguments(p, NULL, NULL, NULL, NULL, a) }
slash_without_default[asdl_seq*]: a=plain_names ',' '/' { a }
slash_with_default[SlashWithDefault*]: a=[n=plain_names ',' { n }] b=names_with_default ',' '/' {
_PyPegen_slash_with_default(p, a, b) }
star_etc[StarEtc*]:
| '*' a=plain_name b=name_with_optional_default* c=[',' d=kwds { d }] [','] {
_PyPegen_star_etc(p, a, b, c) }
| '*' b=name_with_optional_default+ c=[',' d=kwds { d }] [','] {
_PyPegen_star_etc(p, NULL, b, c) }
| a=kwds [','] { _PyPegen_star_etc(p, NULL, NULL, a) }
name_with_optional_default[NameDefaultPair*]:
| ',' a=plain_name b=['=' e=expression { e }] { _PyPegen_name_default_pair(p, a, b) }
names_with_default[asdl_seq*]: a=','.name_with_default+ { a }
name_with_default[NameDefaultPair*]:
| n=plain_name '=' e=expression { _PyPegen_name_default_pair(p, n, e) }
plain_names[asdl_seq*] (memo): a=','.(plain_name !'=')+ { a }
plain_name[arg_ty]:
| a=NAME b=[':' z=annotation { z }] { _Py_arg(a->v.Name.id, b, NULL, EXTRA) }
kwds[arg_ty]:
| '**' a=plain_name { a }
annotation[expr_ty]: expression
decorators[asdl_seq*]: a=('@' f=named_expression NEWLINE { f })+ { a }
class_def[stmt_ty]:
| a=decorators b=class_def_raw { _PyPegen_class_def_decorators(p, a, b) }
| class_def_raw
class_def_raw[stmt_ty]:
| 'class' a=NAME b=['(' z=[arguments] ')' { z }] ':' c=block {
_Py_ClassDef(a->v.Name.id,
(b) ? ((expr_ty) b)->v.Call.args : NULL,
(b) ? ((expr_ty) b)->v.Call.keywords : NULL,
c, NULL, EXTRA) }
block[asdl_seq*] (memo):
| NEWLINE INDENT a=statements DEDENT { a }
| simple_stmt
| invalid_block
expressions_list[asdl_seq*]: a=','.star_expression+ [','] { a }
star_expressions[expr_ty]:
| a=star_expression b=(',' c=star_expression { c })+ [','] {
_Py_Tuple(CHECK(_PyPegen_seq_insert_in_front(p, a, b)), Load, EXTRA) }
| a=star_expression ',' { _Py_Tuple(CHECK(_PyPegen_singleton_seq(p, a)), Load, EXTRA) }
| star_expression
star_expression[expr_ty] (memo):
| '*' a=bitwise_or { _Py_Starred(a, Load, EXTRA) }
| expression
star_named_expressions[asdl_seq*]: a=','.star_named_expression+ [','] { a }
star_named_expression[expr_ty]:
| '*' a=bitwise_or { _Py_Starred(a, Load, EXTRA) }
| named_expression
named_expression[expr_ty]:
| a=NAME ':=' b=expression { _Py_NamedExpr(CHECK(_PyPegen_set_expr_context(p, a, Store)), b, EXTRA) }
| expression !':='
| invalid_named_expression
annotated_rhs[expr_ty]: yield_expr | star_expressions
expressions[expr_ty]:
| a=expression b=(',' c=expression { c })+ [','] {
_Py_Tuple(CHECK(_PyPegen_seq_insert_in_front(p, a, b)), Load, EXTRA) }
| a=expression ',' { _Py_Tuple(CHECK(_PyPegen_singleton_seq(p, a)), Load, EXTRA) }
| expression
expression[expr_ty] (memo):
| a=disjunction 'if' b=disjunction 'else' c=expression { _Py_IfExp(b, a, c, EXTRA) }
| disjunction
| lambdef
lambdef[expr_ty]:
| 'lambda' a=[lambda_parameters] ':' b=expression { _Py_Lambda((a) ? a : CHECK(_PyPegen_empty_arguments(p)), b, EXTRA) }
lambda_parameters[arguments_ty]:
| a=lambda_slash_without_default b=[',' x=lambda_plain_names { x }] c=[',' y=lambda_names_with_default { y }] d=[',' z=[lambda_star_etc] { z }] {
_PyPegen_make_arguments(p, a, NULL, b, c, d) }
| a=lambda_slash_with_default b=[',' y=lambda_names_with_default { y }] c=[',' z=[lambda_star_etc] { z }] {
_PyPegen_make_arguments(p, NULL, a, NULL, b, c) }
| a=lambda_plain_names b=[',' y=lambda_names_with_default { y }] c=[',' z=[lambda_star_etc] { z }] {
_PyPegen_make_arguments(p, NULL, NULL, a, b, c) }
| a=lambda_names_with_default b=[',' z=[lambda_star_etc] { z }] { _PyPegen_make_arguments(p, NULL, NULL, NULL, a, b)}
| a=lambda_star_etc { _PyPegen_make_arguments(p, NULL, NULL, NULL, NULL, a) }
lambda_slash_without_default[asdl_seq*]: a=lambda_plain_names ',' '/' { a }
lambda_slash_with_default[SlashWithDefault*]: a=[n=lambda_plain_names ',' { n }] b=lambda_names_with_default ',' '/' {
_PyPegen_slash_with_default(p, a, b) }
lambda_star_etc[StarEtc*]:
| '*' a=lambda_plain_name b=lambda_name_with_optional_default* c=[',' d=lambda_kwds { d }] [','] {
_PyPegen_star_etc(p, a, b, c) }
| '*' b=lambda_name_with_optional_default+ c=[',' d=lambda_kwds { d }] [','] {
_PyPegen_star_etc(p, NULL, b, c) }
| a=lambda_kwds [','] { _PyPegen_star_etc(p, NULL, NULL, a) }
lambda_name_with_optional_default[NameDefaultPair*]:
| ',' a=lambda_plain_name b=['=' e=expression { e }] { _PyPegen_name_default_pair(p, a, b) }
lambda_names_with_default[asdl_seq*]: a=','.lambda_name_with_default+ { a }
lambda_name_with_default[NameDefaultPair*]:
| n=lambda_plain_name '=' e=expression { _PyPegen_name_default_pair(p, n, e) }
lambda_plain_names[asdl_seq*]: a=','.(lambda_plain_name !'=')+ { a }
lambda_plain_name[arg_ty]: a=NAME { _Py_arg(a->v.Name.id, NULL, NULL, EXTRA) }
lambda_kwds[arg_ty]: '**' a=lambda_plain_name { a }
disjunction[expr_ty] (memo):
| a=conjunction b=('or' c=conjunction { c })+ { _Py_BoolOp(
Or,
CHECK(_PyPegen_seq_insert_in_front(p, a, b)),
EXTRA) }
| conjunction
conjunction[expr_ty] (memo):
| a=inversion b=('and' c=inversion { c })+ { _Py_BoolOp(
And,
CHECK(_PyPegen_seq_insert_in_front(p, a, b)),
EXTRA) }
| inversion
inversion[expr_ty] (memo):
| 'not' a=inversion { _Py_UnaryOp(Not, a, EXTRA) }
| comparison
comparison[expr_ty]:
| a=bitwise_or b=compare_op_bitwise_or_pair+ {
_Py_Compare(a, CHECK(_PyPegen_get_cmpops(p, b)), CHECK(_PyPegen_get_exprs(p, b)), EXTRA) }
| bitwise_or
compare_op_bitwise_or_pair[CmpopExprPair*]:
| eq_bitwise_or
| noteq_bitwise_or
| lte_bitwise_or
| lt_bitwise_or
| gte_bitwise_or
| gt_bitwise_or
| notin_bitwise_or
| in_bitwise_or
| isnot_bitwise_or
| is_bitwise_or
eq_bitwise_or[CmpopExprPair*]: '==' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, Eq, a) }
noteq_bitwise_or[CmpopExprPair*]: '!=' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, NotEq, a) }
lte_bitwise_or[CmpopExprPair*]: '<=' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, LtE, a) }
lt_bitwise_or[CmpopExprPair*]: '<' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, Lt, a) }
gte_bitwise_or[CmpopExprPair*]: '>=' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, GtE, a) }
gt_bitwise_or[CmpopExprPair*]: '>' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, Gt, a) }
notin_bitwise_or[CmpopExprPair*]: 'not' 'in' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, NotIn, a) }
in_bitwise_or[CmpopExprPair*]: 'in' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, In, a) }
isnot_bitwise_or[CmpopExprPair*]: 'is' 'not' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, IsNot, a) }
is_bitwise_or[CmpopExprPair*]: 'is' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, Is, a) }
bitwise_or[expr_ty]:
| a=bitwise_or '|' b=bitwise_xor { _Py_BinOp(a, BitOr, b, EXTRA) }
| bitwise_xor
bitwise_xor[expr_ty]:
| a=bitwise_xor '^' b=bitwise_and { _Py_BinOp(a, BitXor, b, EXTRA) }
| bitwise_and
bitwise_and[expr_ty]:
| a=bitwise_and '&' b=shift_expr { _Py_BinOp(a, BitAnd, b, EXTRA) }
| shift_expr
shift_expr[expr_ty]:
| a=shift_expr '<<' b=sum { _Py_BinOp(a, LShift, b, EXTRA) }
| a=shift_expr '>>' b=sum { _Py_BinOp(a, RShift, b, EXTRA) }
| sum
sum[expr_ty]:
| a=sum '+' b=term { _Py_BinOp(a, Add, b, EXTRA) }
| a=sum '-' b=term { _Py_BinOp(a, Sub, b, EXTRA) }
| term
term[expr_ty]:
| a=term '*' b=factor { _Py_BinOp(a, Mult, b, EXTRA) }
| a=term '/' b=factor { _Py_BinOp(a, Div, b, EXTRA) }
| a=term '//' b=factor { _Py_BinOp(a, FloorDiv, b, EXTRA) }
| a=term '%' b=factor { _Py_BinOp(a, Mod, b, EXTRA) }
| a=term '@' b=factor { _Py_BinOp(a, MatMult, b, EXTRA) }
| factor
factor[expr_ty] (memo):
| '+' a=factor { _Py_UnaryOp(UAdd, a, EXTRA) }
| '-' a=factor { _Py_UnaryOp(USub, a, EXTRA) }
| '~' a=factor { _Py_UnaryOp(Invert, a, EXTRA) }
| power
power[expr_ty]:
| a=await_primary '**' b=factor { _Py_BinOp(a, Pow, b, EXTRA) }
| await_primary
await_primary[expr_ty] (memo):
| AWAIT a=primary { _Py_Await(a, EXTRA) }
| primary
primary[expr_ty]:
| a=primary '.' b=NAME { _Py_Attribute(a, b->v.Name.id, Load, EXTRA) }
| a=primary b=genexp { _Py_Call(a, CHECK(_PyPegen_singleton_seq(p, b)), NULL, EXTRA) }
| a=primary '(' b=[arguments] ')' {
_Py_Call(a,
(b) ? ((expr_ty) b)->v.Call.args : NULL,
(b) ? ((expr_ty) b)->v.Call.keywords : NULL,
EXTRA) }
| a=primary '[' b=slices ']' { _Py_Subscript(a, b, Load, EXTRA) }
| atom
slices[expr_ty]:
| a=slice !',' { a }
| a=','.slice+ [','] { _Py_Tuple(a, Load, EXTRA) }
slice[expr_ty]:
| a=[expression] ':' b=[expression] c=[':' d=[expression] { d }] { _Py_Slice(a, b, c, EXTRA) }
| a=expression { a }
atom[expr_ty]:
| NAME
| 'True' { _Py_Constant(Py_True, NULL, EXTRA) }
| 'False' { _Py_Constant(Py_False, NULL, EXTRA) }
| 'None' { _Py_Constant(Py_None, NULL, EXTRA) }
| '__new_parser__' { RAISE_SYNTAX_ERROR("You found it!") }
| &STRING strings
| NUMBER
| &'(' (tuple | group | genexp)
| &'[' (list | listcomp)
| &'{' (dict | set | dictcomp | setcomp)
| '...' { _Py_Constant(Py_Ellipsis, NULL, EXTRA) }
strings[expr_ty] (memo): a=STRING+ { _PyPegen_concatenate_strings(p, a) }
list[expr_ty]:
| '[' a=[star_named_expressions] ']' { _Py_List(a, Load, EXTRA) }
listcomp[expr_ty]:
| '[' a=named_expression b=for_if_clauses ']' { _Py_ListComp(a, b, EXTRA) }
| invalid_comprehension
tuple[expr_ty]:
| '(' a=[y=star_named_expression ',' z=[star_named_expressions] { _PyPegen_seq_insert_in_front(p, y, z) } ] ')' {
_Py_Tuple(a, Load, EXTRA) }
group[expr_ty]: '(' a=(yield_expr | named_expression) ')' { a }
genexp[expr_ty]:
| '(' a=expression b=for_if_clauses ')' { _Py_GeneratorExp(a, b, EXTRA) }
| invalid_comprehension
set[expr_ty]: '{' a=expressions_list '}' { _Py_Set(a, EXTRA) }
setcomp[expr_ty]:
| '{' a=expression b=for_if_clauses '}' { _Py_SetComp(a, b, EXTRA) }
| invalid_comprehension
dict[expr_ty]:
| '{' a=[kvpairs] '}' { _Py_Dict(CHECK(_PyPegen_get_keys(p, a)),
CHECK(_PyPegen_get_values(p, a)), EXTRA) }
dictcomp[expr_ty]:
| '{' a=kvpair b=for_if_clauses '}' { _Py_DictComp(a->key, a->value, b, EXTRA) }
kvpairs[asdl_seq*]: a=','.kvpair+ [','] { a }
kvpair[KeyValuePair*]:
| '**' a=bitwise_or { _PyPegen_key_value_pair(p, NULL, a) }
| a=expression ':' b=expression { _PyPegen_key_value_pair(p, a, b) }
for_if_clauses[asdl_seq*]:
| a=(y=[ASYNC] 'for' a=star_targets 'in' b=disjunction c=('if' z=disjunction { z })*
{ _Py_comprehension(a, b, c, y != NULL, p->arena) })+ { a }
yield_expr[expr_ty]:
| 'yield' 'from' a=expression { _Py_YieldFrom(a, EXTRA) }
| 'yield' a=[star_expressions] { _Py_Yield(a, EXTRA) }
arguments[expr_ty] (memo):
| a=args [','] &')' { a }
| incorrect_arguments
args[expr_ty]:
| a=starred_expression b=[',' c=args { c }] {
_Py_Call(_PyPegen_dummy_name(p),
(b) ? CHECK(_PyPegen_seq_insert_in_front(p, a, ((expr_ty) b)->v.Call.args))
: CHECK(_PyPegen_singleton_seq(p, a)),
(b) ? ((expr_ty) b)->v.Call.keywords : NULL,
EXTRA) }
| a=kwargs { _Py_Call(_PyPegen_dummy_name(p),
CHECK_NULL_ALLOWED(_PyPegen_seq_extract_starred_exprs(p, a)),
CHECK_NULL_ALLOWED(_PyPegen_seq_delete_starred_exprs(p, a)),
EXTRA) }
| a=named_expression b=[',' c=args { c }] {
_Py_Call(_PyPegen_dummy_name(p),
(b) ? CHECK(_PyPegen_seq_insert_in_front(p, a, ((expr_ty) b)->v.Call.args))
: CHECK(_PyPegen_singleton_seq(p, a)),
(b) ? ((expr_ty) b)->v.Call.keywords : NULL,
EXTRA) }
kwargs[asdl_seq*]:
| a=','.kwarg_or_starred+ ',' b=','.kwarg_or_double_starred+ { _PyPegen_join_sequences(p, a, b) }
| ','.kwarg_or_starred+
| ','.kwarg_or_double_starred+
starred_expression[expr_ty]:
| '*' a=expression { _Py_Starred(a, Load, EXTRA) }
kwarg_or_starred[KeywordOrStarred*]:
| a=NAME '=' b=expression {
_PyPegen_keyword_or_starred(p, CHECK(_Py_keyword(a->v.Name.id, b, EXTRA)), 1) }
| a=starred_expression { _PyPegen_keyword_or_starred(p, a, 0) }
kwarg_or_double_starred[KeywordOrStarred*]:
| a=NAME '=' b=expression {
_PyPegen_keyword_or_starred(p, CHECK(_Py_keyword(a->v.Name.id, b, EXTRA)), 1) }
| '**' a=expression { _PyPegen_keyword_or_starred(p, CHECK(_Py_keyword(NULL, a, EXTRA)), 1) }
# NOTE: star_targets may contain *bitwise_or, targets may not.
star_targets[expr_ty]:
| a=star_target !',' { a }
| a=star_target b=(',' c=star_target { c })* [','] {
_Py_Tuple(CHECK(_PyPegen_seq_insert_in_front(p, a, b)), Store, EXTRA) }
star_targets_seq[asdl_seq*]: a=','.star_target+ [','] { a }
star_target[expr_ty] (memo):
| '*' a=(!'*' star_target) {
_Py_Starred(CHECK(_PyPegen_set_expr_context(p, a, Store)), Store, EXTRA) }
| a=t_primary '.' b=NAME !t_lookahead { _Py_Attribute(a, b->v.Name.id, Store, EXTRA) }
| a=t_primary '[' b=slices ']' !t_lookahead { _Py_Subscript(a, b, Store, EXTRA) }
| star_atom
star_atom[expr_ty]:
| a=NAME { _PyPegen_set_expr_context(p, a, Store) }
| '(' a=star_target ')' { _PyPegen_set_expr_context(p, a, Store) }
| '(' a=[star_targets_seq] ')' { _Py_Tuple(a, Store, EXTRA) }
| '[' a=[star_targets_seq] ']' { _Py_List(a, Store, EXTRA) }
inside_paren_ann_assign_target[expr_ty]:
| ann_assign_subscript_attribute_target
| a=NAME { _PyPegen_set_expr_context(p, a, Store) }
| '(' a=inside_paren_ann_assign_target ')' { a }
ann_assign_subscript_attribute_target[expr_ty]:
| a=t_primary '.' b=NAME !t_lookahead { _Py_Attribute(a, b->v.Name.id, Store, EXTRA) }
| a=t_primary '[' b=slices ']' !t_lookahead { _Py_Subscript(a, b, Store, EXTRA) }
del_targets[asdl_seq*]: a=','.del_target+ [','] { a }
del_target[expr_ty] (memo):
| a=t_primary '.' b=NAME !t_lookahead { _Py_Attribute(a, b->v.Name.id, Del, EXTRA) }
| a=t_primary '[' b=slices ']' !t_lookahead { _Py_Subscript(a, b, Del, EXTRA) }
| del_t_atom
del_t_atom[expr_ty]:
| a=NAME { _PyPegen_set_expr_context(p, a, Del) }
| '(' a=del_target ')' { _PyPegen_set_expr_context(p, a, Del) }
| '(' a=[del_targets] ')' { _Py_Tuple(a, Del, EXTRA) }
| '[' a=[del_targets] ']' { _Py_List(a, Del, EXTRA) }
targets[asdl_seq*]: a=','.target+ [','] { a }
target[expr_ty] (memo):
| a=t_primary '.' b=NAME !t_lookahead { _Py_Attribute(a, b->v.Name.id, Store, EXTRA) }
| a=t_primary '[' b=slices ']' !t_lookahead { _Py_Subscript(a, b, Store, EXTRA) }
| t_atom
t_primary[expr_ty]:
| a=t_primary '.' b=NAME &t_lookahead { _Py_Attribute(a, b->v.Name.id, Load, EXTRA) }
| a=t_primary '[' b=slices ']' &t_lookahead { _Py_Subscript(a, b, Load, EXTRA) }
| a=t_primary b=genexp &t_lookahead { _Py_Call(a, CHECK(_PyPegen_singleton_seq(p, b)), NULL, EXTRA) }
| a=t_primary '(' b=[arguments] ')' &t_lookahead {
_Py_Call(a,
(b) ? ((expr_ty) b)->v.Call.args : NULL,
(b) ? ((expr_ty) b)->v.Call.keywords : NULL,
EXTRA) }
| a=atom &t_lookahead { a }
t_lookahead: '(' | '[' | '.'
t_atom[expr_ty]:
| a=NAME { _PyPegen_set_expr_context(p, a, Store) }
| '(' a=target ')' { _PyPegen_set_expr_context(p, a, Store) }
| '(' b=[targets] ')' { _Py_Tuple(b, Store, EXTRA) }
| '[' b=[targets] ']' { _Py_List(b, Store, EXTRA) }
# From here on, there are rules for invalid syntax with specialised error messages
incorrect_arguments:
| args ',' '*' { RAISE_SYNTAX_ERROR("iterable argument unpacking follows keyword argument unpacking") }
| expression for_if_clauses ',' [args | expression for_if_clauses] {
RAISE_SYNTAX_ERROR("Generator expression must be parenthesized") }
| a=args ',' args { _PyPegen_arguments_parsing_error(p, a) }
invalid_named_expression:
| a=expression ':=' expression {
RAISE_SYNTAX_ERROR("cannot use assignment expressions with %s", _PyPegen_get_expr_name(a)) }
invalid_assignment:
| list ':' { RAISE_SYNTAX_ERROR("only single target (not list) can be annotated") }
| tuple ':' { RAISE_SYNTAX_ERROR("only single target (not tuple) can be annotated") }
| expression ':' expression ['=' annotated_rhs] {
RAISE_SYNTAX_ERROR("illegal target for annotation") }
| a=expression ('=' | augassign) (yield_expr | star_expressions) {
RAISE_SYNTAX_ERROR("cannot assign to %s", _PyPegen_get_expr_name(a)) }
invalid_block:
| NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block") }
invalid_comprehension:
| ('[' | '(' | '{') '*' expression for_if_clauses {
RAISE_SYNTAX_ERROR("iterable unpacking cannot be used in comprehension") }
invalid_parameters:
| [plain_names ','] (slash_with_default | names_with_default) ',' plain_names {
RAISE_SYNTAX_ERROR("non-default argument follows default argument") }

3
Include/compile.h
View File

@ -108,4 +108,7 @@ PyAPI_FUNC(int) _PyAST_Optimize(struct _mod *, PyArena *arena, _PyASTOptimizeSta
#define Py_eval_input 258
#define Py_func_type_input 345
/* This doesn't need to match anything */
#define Py_fstring_input 800
#endif /* !Py_COMPILE_H */

4
Include/cpython/initconfig.h
View File

@ -147,6 +147,10 @@ typedef struct {
Set to 1 by -X faulthandler and PYTHONFAULTHANDLER. -1 means unset. */
int faulthandler;
/* Enable PEG parser?
1 by default, set to 0 by -X oldparser and PYTHONOLDPARSER */
int use_peg;
/* Enable tracemalloc?
Set by -X tracemalloc=N and PYTHONTRACEMALLOC. -1 means unset */
int tracemalloc;

32
Include/pegen_interface.h Normal file
View File

@ -0,0 +1,32 @@
#ifndef Py_LIMITED_API
#ifndef Py_PEGENINTERFACE
#define Py_PEGENINTERFACE
#ifdef __cplusplus
extern "C" {
#endif
#include "Python.h"
#include "Python-ast.h"
PyAPI_FUNC(mod_ty) PyPegen_ASTFromFile(const char *filename, int mode, PyArena *arena);
PyAPI_FUNC(mod_ty) PyPegen_ASTFromString(const char *str, int mode, PyCompilerFlags *flags,
PyArena *arena);
PyAPI_FUNC(mod_ty) PyPegen_ASTFromStringObject(const char *str, PyObject* filename, int mode,
PyCompilerFlags *flags, PyArena *arena);
PyAPI_FUNC(mod_ty) PyPegen_ASTFromFileObject(FILE *fp, PyObject *filename_ob,
int mode, const char *enc, const char *ps1,
const char *ps2, int *errcode, PyArena *arena);
PyAPI_FUNC(PyCodeObject *) PyPegen_CodeObjectFromFile(const char *filename, int mode);
PyAPI_FUNC(PyCodeObject *) PyPegen_CodeObjectFromString(const char *str, int mode,
PyCompilerFlags *flags);
PyAPI_FUNC(PyCodeObject *) PyPegen_CodeObjectFromFileObject(FILE *, PyObject *filename_ob,
int mode, const char *enc,
const char *ps1,
const char *ps2,
int *errcode);
#ifdef __cplusplus
}
#endif
#endif /* !Py_PEGENINTERFACE*/
#endif /* !Py_LIMITED_API */

19
Lib/test/test_cmd_line_script.py
View File

@ -599,7 +599,7 @@ class CmdLineTest(unittest.TestCase):
exitcode, stdout, stderr = assert_python_failure(script_name)
text = io.TextIOWrapper(io.BytesIO(stderr), 'ascii').read()
# Confirm that the caret is located under the first 1 character
self.assertIn("\n 1 + 1 = 2\n ^", text)
self.assertIn("\n 1 + 1 = 2\n ^", text)
def test_syntaxerror_indented_caret_position(self):
script = textwrap.dedent("""\
@ -611,7 +611,7 @@ class CmdLineTest(unittest.TestCase):
exitcode, stdout, stderr = assert_python_failure(script_name)
text = io.TextIOWrapper(io.BytesIO(stderr), 'ascii').read()
# Confirm that the caret is located under the first 1 character
self.assertIn("\n 1 + 1 = 2\n ^", text)
self.assertIn("\n 1 + 1 = 2\n ^", text)
# Try the same with a form feed at the start of the indented line
script = (
@ -622,7 +622,7 @@ class CmdLineTest(unittest.TestCase):
exitcode, stdout, stderr = assert_python_failure(script_name)
text = io.TextIOWrapper(io.BytesIO(stderr), "ascii").read()
self.assertNotIn("\f", text)
self.assertIn("\n 1 + 1 = 2\n ^", text)
self.assertIn("\n 1 + 1 = 2\n ^", text)
def test_syntaxerror_multi_line_fstring(self):
script = 'foo = f"""{}\nfoo"""\n'
@ -632,14 +632,14 @@ class CmdLineTest(unittest.TestCase):
self.assertEqual(
stderr.splitlines()[-3:],
[
b' foo = f"""{}',
b' ^',
b' foo"""',
b' ^',
b'SyntaxError: f-string: empty expression not allowed',
],
)
def test_syntaxerror_invalid_escape_sequence_multi_line(self):
script = 'foo = """\\q\n"""\n'
script = 'foo = """\\q"""\n'
with support.temp_dir() as script_dir:
script_name = _make_test_script(script_dir, 'script', script)
exitcode, stdout, stderr = assert_python_failure(
@ -647,10 +647,9 @@ class CmdLineTest(unittest.TestCase):
)
self.assertEqual(
stderr.splitlines()[-3:],
[
b' foo = """\\q',
b' ^',
b'SyntaxError: invalid escape sequence \\q',
[ b' foo = """\\q"""',
b' ^',
b'SyntaxError: invalid escape sequence \\q'
],
)

3
Lib/test/test_codeop.py
View File

@ -2,6 +2,7 @@
Test cases for codeop.py
Nick Mathewson
"""
import sys
import unittest
from test.support import is_jython
@ -9,7 +10,6 @@ from codeop import compile_command, PyCF_DONT_IMPLY_DEDENT
import io
if is_jython:
import sys
def unify_callables(d):
for n,v in d.items():
@ -122,6 +122,7 @@ class CodeopTests(unittest.TestCase):
av("def f():\n pass\n#foo\n")
av("@a.b.c\ndef f():\n pass\n")
@unittest.skipIf(sys.flags.use_peg, "Pegen does not support PyCF_DONT_INPLY_DEDENT yet")
def test_incomplete(self):
ai = self.assertIncomplete

1
Lib/test/test_compile.py
View File

@ -501,6 +501,7 @@ if 1:
self.compile_single("if x:\n f(x)\nelse:\n g(x)")
self.compile_single("class T:\n pass")
@unittest.skipIf(sys.flags.use_peg, 'Pegen does not disallow multiline single stmts')
def test_bad_single_statement(self):
self.assertInvalidSingle('1\n2')
self.assertInvalidSingle('def f(): pass')

2
Lib/test/test_embed.py
View File

@ -347,6 +347,7 @@ class InitConfigTests(EmbeddingTestsMixin, unittest.TestCase):
'isolated': 0,
'use_environment': 1,
'dev_mode': 0,
'use_peg': 1,
'install_signal_handlers': 1,
'use_hash_seed': 0,
@ -728,6 +729,7 @@ class InitConfigTests(EmbeddingTestsMixin, unittest.TestCase):
'import_time': 1,
'show_ref_count': 1,
'malloc_stats': 1,
'use_peg': 0,
'stdio_encoding': 'iso8859-1',
'stdio_errors': 'replace',

2
Lib/test/test_eof.py
View File

@ -26,6 +26,7 @@ class EOFTestCase(unittest.TestCase):
else:
raise support.TestFailed
@unittest.skipIf(sys.flags.use_peg, "TODO for PEG -- fails with new parser")
def test_line_continuation_EOF(self):
"""A continuation at the end of input must be an error; bpo2180."""
expect = 'unexpected EOF while parsing (<string>, line 1)'
@ -36,6 +37,7 @@ class EOFTestCase(unittest.TestCase):
exec('\\')
self.assertEqual(str(excinfo.exception), expect)
@unittest.skip("TODO for PEG -- fails even with old parser now")
@unittest.skipIf(not sys.executable, "sys.executable required")
def test_line_continuation_EOF_from_file_bpo2180(self):
"""Ensure tok_nextc() does not add too many ending newlines."""

1
Lib/test/test_exceptions.py
View File

@ -178,6 +178,7 @@ class ExceptionTests(unittest.TestCase):
s = '''if True:\n print()\n\texec "mixed tabs and spaces"'''
ckmsg(s, "inconsistent use of tabs and spaces in indentation", TabError)
@unittest.skipIf(sys.flags.use_peg, "Pegen column offsets might be different")
def testSyntaxErrorOffset(self):
def check(src, lineno, offset, encoding='utf-8'):
with self.assertRaises(SyntaxError) as cm:

3
Lib/test/test_flufl.py
View File

@ -1,6 +1,9 @@
import __future__
import unittest
import sys
@unittest.skipIf(sys.flags.use_peg, "Not supported by pegen yet")
class FLUFLTests(unittest.TestCase):
def test_barry_as_bdfl(self):

4
Lib/test/test_fstring.py
View File

@ -10,6 +10,7 @@
import ast
import types
import decimal
import sys
import unittest
a_global = 'global variable'
@ -205,7 +206,8 @@ f'{a * f"-{x()}-"}'"""
call = binop.right.values[1].value
self.assertEqual(type(call), ast.Call)
self.assertEqual(call.lineno, 3)
self.assertEqual(call.col_offset, 11)
if not sys.flags.use_peg:
self.assertEqual(call.col_offset, 11)
def test_ast_line_numbers_duplicate_expression(self):
"""Duplicate expression

9
Lib/test/test_generators.py
View File

@ -1856,10 +1856,11 @@ Traceback (most recent call last):
...
SyntaxError: 'yield' outside function
>>> def f(): x = yield = y
Traceback (most recent call last):
...
SyntaxError: assignment to yield expression not possible
# Pegen does not produce this error message yet
# >>> def f(): x = yield = y
# Traceback (most recent call last):
# ...
# SyntaxError: assignment to yield expression not possible
>>> def f(): (yield bar) = y
Traceback (most recent call last):

4
Lib/test/test_parser.py
View File

@ -8,6 +8,7 @@ import pickle
import unittest
import operator
import struct
import sys
from test import support
from test.support.script_helper import assert_python_failure
from test.support.script_helper import assert_python_ok
@ -899,9 +900,10 @@ class ParserStackLimitTestCase(unittest.TestCase):
st = parser.expr(e)
st.compile()
@unittest.skipIf(sys.flags.use_peg, "Pegen does not trigger memory error with this many parenthesis")
def test_trigger_memory_error(self):
e = self._nested_expression(100)
rc, out, err = assert_python_failure('-c', e)
rc, out, err = assert_python_failure('-Xoldparser', '-c', e)
# parsing the expression will result in an error message
# followed by a MemoryError (see #11963)
self.assertIn(b's_push: parser stack overflow', err)

7
Lib/test/test_peg_generator/__init__.py Normal file
View File

@ -0,0 +1,7 @@
import os
from test.support import load_package_tests
# Load all tests in package
def load_tests(*args):
return load_package_tests(os.path.dirname(__file__), *args)

4
Lib/test/test_peg_generator/__main__.py Normal file
View File

@ -0,0 +1,4 @@
import unittest
from . import load_tests
unittest.main()

62
Lib/test/test_peg_generator/ast_dump.py Normal file
View File

@ -0,0 +1,62 @@
"""
Copy-parse of ast.dump, removing the `isinstance` checks. This is needed,
because testing pegen requires generating a C extension module, which contains
a copy of the symbols defined in Python-ast.c. Thus, the isinstance check would
always fail. We rely on string comparison of the base classes instead.
TODO: Remove the above-described hack.
"""
def ast_dump(node, annotate_fields=True, include_attributes=False, *, indent=None):
def _format(node, level=0):
if indent is not None:
level += 1
prefix = '\n' + indent * level
sep = ',\n' + indent * level
else:
prefix = ''
sep = ', '
if any(cls.__name__ == 'AST' for cls in node.__class__.__mro__):
cls = type(node)
args = []
allsimple = True
keywords = annotate_fields
for name in node._fields:
try:
value = getattr(node, name)
except AttributeError:
keywords = True
continue
if value is None and getattr(cls, name, ...) is None:
keywords = True
continue
value, simple = _format(value, level)
allsimple = allsimple and simple
if keywords:
args.append('%s=%s' % (name, value))
else:
args.append(value)
if include_attributes and node._attributes:
for name in node._attributes:
try:
value = getattr(node, name)
except AttributeError:
continue
if value is None and getattr(cls, name, ...) is None:
continue
value, simple = _format(value, level)
allsimple = allsimple and simple
args.append('%s=%s' % (name, value))
if allsimple and len(args) <= 3:
return '%s(%s)' % (node.__class__.__name__, ', '.join(args)), not args
return '%s(%s%s)' % (node.__class__.__name__, prefix, sep.join(args)), False
elif isinstance(node, list):
if not node:
return '[]', True
return '[%s%s]' % (prefix, sep.join(_format(x, level)[0] for x in node)), False
return repr(node), True
if all(cls.__name__ != 'AST' for cls in node.__class__.__mro__):
raise TypeError('expected AST, got %r' % node.__class__.__name__)
if indent is not None and not isinstance(indent, str):
indent = ' ' * indent
return _format(node)[0]

333
Lib/test/test_peg_generator/test_c_parser.py Normal file
View File

@ -0,0 +1,333 @@
import ast
import contextlib
import traceback
import tempfile
import shutil
import unittest
import sys
from test import test_tools
from test.test_peg_generator.ast_dump import ast_dump
from pathlib import PurePath, Path
from typing import Sequence
test_tools.skip_if_missing('peg_generator')
with test_tools.imports_under_tool('peg_generator'):
from pegen.grammar_parser import GeneratedParser as GrammarParser
from pegen.testutil import (
parse_string,
generate_parser_c_extension,
generate_c_parser_source,
)
class TestCParser(unittest.TestCase):
def setUp(self):
self.tmp_path = tempfile.mkdtemp()
def tearDown(self):
with contextlib.suppress(PermissionError):
shutil.rmtree(self.tmp_path)
def check_input_strings_for_grammar(
self,
source: str,
tmp_path: PurePath,
valid_cases: Sequence[str] = (),
invalid_cases: Sequence[str] = (),
) -> None:
grammar = parse_string(source, GrammarParser)
extension = generate_parser_c_extension(grammar, Path(tmp_path))
if valid_cases:
for case in valid_cases:
extension.parse_string(case, mode=0)
if invalid_cases:
for case in invalid_cases:
with self.assertRaises(SyntaxError):
extension.parse_string(case, mode=0)
def verify_ast_generation(self, source: str, stmt: str, tmp_path: PurePath) -> None:
grammar = parse_string(source, GrammarParser)
extension = generate_parser_c_extension(grammar, Path(tmp_path))
expected_ast = ast.parse(stmt)
actual_ast = extension.parse_string(stmt, mode=1)
self.assertEqual(ast_dump(expected_ast), ast_dump(actual_ast))
def test_c_parser(self) -> None:
grammar_source = """
start[mod_ty]: a=stmt* $ { Module(a, NULL, p->arena) }
stmt[stmt_ty]: a=expr_stmt { a }
expr_stmt[stmt_ty]: a=expression NEWLINE { _Py_Expr(a, EXTRA) }
expression[expr_ty]: ( l=expression '+' r=term { _Py_BinOp(l, Add, r, EXTRA) }
| l=expression '-' r=term { _Py_BinOp(l, Sub, r, EXTRA) }
| t=term { t }
)
term[expr_ty]: ( l=term '*' r=factor { _Py_BinOp(l, Mult, r, EXTRA) }
| l=term '/' r=factor { _Py_BinOp(l, Div, r, EXTRA) }
| f=factor { f }
)
factor[expr_ty]: ('(' e=expression ')' { e }
| a=atom { a }
)
atom[expr_ty]: ( n=NAME { n }
| n=NUMBER { n }
| s=STRING { s }
)
"""
grammar = parse_string(grammar_source, GrammarParser)
extension = generate_parser_c_extension(grammar, Path(self.tmp_path))
expressions = [
"4+5",
"4-5",
"4*5",
"1+4*5",
"1+4/5",
"(1+1) + (1+1)",
"(1+1) - (1+1)",
"(1+1) * (1+1)",
"(1+1) / (1+1)",
]
for expr in expressions:
the_ast = extension.parse_string(expr, mode=1)
expected_ast = ast.parse(expr)
self.assertEqual(ast_dump(the_ast), ast_dump(expected_ast))
def test_lookahead(self) -> None:
grammar = """
start: NAME &NAME expr NEWLINE? ENDMARKER
expr: NAME | NUMBER
"""
valid_cases = ["foo bar"]
invalid_cases = ["foo 34"]
self.check_input_strings_for_grammar(grammar, self.tmp_path, valid_cases, invalid_cases)
def test_negative_lookahead(self) -> None:
grammar = """
start: NAME !NAME expr NEWLINE? ENDMARKER
expr: NAME | NUMBER
"""
valid_cases = ["foo 34"]
invalid_cases = ["foo bar"]
self.check_input_strings_for_grammar(grammar, self.tmp_path, valid_cases, invalid_cases)
def test_cut(self) -> None:
grammar = """
start: X ~ Y Z | X Q S
X: 'x'
Y: 'y'
Z: 'z'
Q: 'q'
S: 's'
"""
valid_cases = ["x y z"]
invalid_cases = ["x q s"]
self.check_input_strings_for_grammar(grammar, self.tmp_path, valid_cases, invalid_cases)
def test_gather(self) -> None:
grammar = """
start: ';'.pass_stmt+ NEWLINE
pass_stmt: 'pass'
"""
valid_cases = ["pass", "pass; pass"]
invalid_cases = ["pass;", "pass; pass;"]
self.check_input_strings_for_grammar(grammar, self.tmp_path, valid_cases, invalid_cases)
def test_left_recursion(self) -> None:
grammar = """
start: expr NEWLINE
expr: ('-' term | expr '+' term | term)
term: NUMBER
"""
valid_cases = ["-34", "34", "34 + 12", "1 + 1 + 2 + 3"]
self.check_input_strings_for_grammar(grammar, self.tmp_path, valid_cases)
def test_advanced_left_recursive(self) -> None:
grammar = """
start: NUMBER | sign start
sign: ['-']
"""
valid_cases = ["23", "-34"]
self.check_input_strings_for_grammar(grammar, self.tmp_path, valid_cases)
def test_mutually_left_recursive(self) -> None:
grammar = """
start: foo 'E'
foo: bar 'A' | 'B'
bar: foo 'C' | 'D'
"""
valid_cases = ["B E", "D A C A E"]
self.check_input_strings_for_grammar(grammar, self.tmp_path, valid_cases)
def test_nasty_mutually_left_recursive(self) -> None:
grammar = """
start: target '='
target: maybe '+' | NAME
maybe: maybe '-' | target
"""
valid_cases = ["x ="]
invalid_cases = ["x - + ="]
self.check_input_strings_for_grammar(grammar, self.tmp_path, valid_cases, invalid_cases)
def test_return_stmt_noexpr_action(self) -> None:
grammar = """
start[mod_ty]: a=[statements] ENDMARKER { Module(a, NULL, p->arena) }
statements[asdl_seq*]: a=statement+ { a }
statement[stmt_ty]: simple_stmt
simple_stmt[stmt_ty]: small_stmt
small_stmt[stmt_ty]: return_stmt
return_stmt[stmt_ty]: a='return' NEWLINE { _Py_Return(NULL, EXTRA) }
"""
stmt = "return"
self.verify_ast_generation(grammar, stmt, self.tmp_path)
def test_gather_action_ast(self) -> None:
grammar = """
start[mod_ty]: a=';'.pass_stmt+ NEWLINE ENDMARKER { Module(a, NULL, p->arena) }
pass_stmt[stmt_ty]: a='pass' { _Py_Pass(EXTRA)}
"""
stmt = "pass; pass"
self.verify_ast_generation(grammar, stmt, self.tmp_path)
def test_pass_stmt_action(self) -> None:
grammar = """
start[mod_ty]: a=[statements] ENDMARKER { Module(a, NULL, p->arena) }
statements[asdl_seq*]: a=statement+ { a }
statement[stmt_ty]: simple_stmt
simple_stmt[stmt_ty]: small_stmt
small_stmt[stmt_ty]: pass_stmt
pass_stmt[stmt_ty]: a='pass' NEWLINE { _Py_Pass(EXTRA) }
"""
stmt = "pass"
self.verify_ast_generation(grammar, stmt, self.tmp_path)
def test_if_stmt_action(self) -> None:
grammar = """
start[mod_ty]: a=[statements] ENDMARKER { Module(a, NULL, p->arena) }
statements[asdl_seq*]: a=statement+ { _PyPegen_seq_flatten(p, a) }
statement[asdl_seq*]: a=compound_stmt { _PyPegen_singleton_seq(p, a) } | simple_stmt
simple_stmt[asdl_seq*]: a=small_stmt b=further_small_stmt* [';'] NEWLINE { _PyPegen_seq_insert_in_front(p, a, b) }
further_small_stmt[stmt_ty]: ';' a=small_stmt { a }
block: simple_stmt | NEWLINE INDENT a=statements DEDENT { a }
compound_stmt: if_stmt
if_stmt: 'if' a=full_expression ':' b=block { _Py_If(a, b, NULL, EXTRA) }
small_stmt[stmt_ty]: pass_stmt
pass_stmt[stmt_ty]: a='pass' { _Py_Pass(EXTRA) }
full_expression: NAME
"""
stmt = "pass"
self.verify_ast_generation(grammar, stmt, self.tmp_path)
def test_same_name_different_types(self) -> None:
source = """
start[mod_ty]: a=import_from+ NEWLINE ENDMARKER { Module(a, NULL, p->arena)}
import_from[stmt_ty]: ( a='from' !'import' c=simple_name 'import' d=import_as_names_from {
_Py_ImportFrom(c->v.Name.id, d, 0, EXTRA) }
| a='from' '.' 'import' c=import_as_names_from {
_Py_ImportFrom(NULL, c, 1, EXTRA) }
)
simple_name[expr_ty]: NAME
import_as_names_from[asdl_seq*]: a=','.import_as_name_from+ { a }
import_as_name_from[alias_ty]: a=NAME 'as' b=NAME { _Py_alias(((expr_ty) a)->v.Name.id, ((expr_ty) b)->v.Name.id, p->arena) }
"""
grammar = parse_string(source, GrammarParser)
extension = generate_parser_c_extension(grammar, Path(self.tmp_path))
for stmt in ("from a import b as c", "from . import a as b"):
expected_ast = ast.parse(stmt)
actual_ast = extension.parse_string(stmt, mode=1)
self.assertEqual(ast_dump(expected_ast), ast_dump(actual_ast))
def test_with_stmt_with_paren(self) -> None:
grammar_source = """
start[mod_ty]: a=[statements] ENDMARKER { Module(a, NULL, p->arena) }
statements[asdl_seq*]: a=statement+ { _PyPegen_seq_flatten(p, a) }
statement[asdl_seq*]: a=compound_stmt { _PyPegen_singleton_seq(p, a) }
compound_stmt[stmt_ty]: with_stmt
with_stmt[stmt_ty]: (
a='with' '(' b=','.with_item+ ')' ':' c=block {
_Py_With(b, _PyPegen_singleton_seq(p, c), NULL, EXTRA) }
)
with_item[withitem_ty]: (
e=NAME o=['as' t=NAME { t }] { _Py_withitem(e, _PyPegen_set_expr_context(p, o, Store), p->arena) }
)
block[stmt_ty]: a=pass_stmt NEWLINE { a } | NEWLINE INDENT a=pass_stmt DEDENT { a }
pass_stmt[stmt_ty]: a='pass' { _Py_Pass(EXTRA) }
"""
stmt = "with (\n a as b,\n c as d\n): pass"
grammar = parse_string(grammar_source, GrammarParser)
extension = generate_parser_c_extension(grammar, Path(self.tmp_path))
the_ast = extension.parse_string(stmt, mode=1)
self.assertTrue(ast_dump(the_ast).startswith(
"Module(body=[With(items=[withitem(context_expr=Name(id='a', ctx=Load()), optional_vars=Name(id='b', ctx=Store())), "
"withitem(context_expr=Name(id='c', ctx=Load()), optional_vars=Name(id='d', ctx=Store()))]"
))
def test_ternary_operator(self) -> None:
grammar_source = """
start[mod_ty]: a=expr ENDMARKER { Module(a, NULL, p->arena) }
expr[asdl_seq*]: a=listcomp NEWLINE { _PyPegen_singleton_seq(p, _Py_Expr(a, EXTRA)) }
listcomp[expr_ty]: (
a='[' b=NAME c=for_if_clauses d=']' { _Py_ListComp(b, c, EXTRA) }
)
for_if_clauses[asdl_seq*]: (
a=(y=[ASYNC] 'for' a=NAME 'in' b=NAME c=('if' z=NAME { z })*
{ _Py_comprehension(_Py_Name(((expr_ty) a)->v.Name.id, Store, EXTRA), b, c, (y == NULL) ? 0 : 1, p->arena) })+ { a }
)
"""
stmt = "[i for i in a if b]"
self.verify_ast_generation(grammar_source, stmt, self.tmp_path)
def test_syntax_error_for_string(self) -> None:
grammar_source = """
start: expr+ NEWLINE? ENDMARKER
expr: NAME
"""
grammar = parse_string(grammar_source, GrammarParser)
print(list(Path(self.tmp_path).iterdir()))
extension = generate_parser_c_extension(grammar, Path(self.tmp_path))
for text in ("a b 42 b a", "名 名 42 名 名"):
try:
extension.parse_string(text, mode=0)
except SyntaxError as e:
tb = traceback.format_exc()
self.assertTrue('File "<string>", line 1' in tb)
self.assertTrue(f"SyntaxError: invalid syntax" in tb)
def test_headers_and_trailer(self) -> None:
grammar_source = """
@header 'SOME HEADER'
@subheader 'SOME SUBHEADER'
@trailer 'SOME TRAILER'
start: expr+ NEWLINE? ENDMARKER
expr: x=NAME
"""
grammar = parse_string(grammar_source, GrammarParser)
parser_source = generate_c_parser_source(grammar)
self.assertTrue("SOME HEADER" in parser_source)
self.assertTrue("SOME SUBHEADER" in parser_source)
self.assertTrue("SOME TRAILER" in parser_source)
def test_error_in_rules(self) -> None:
grammar_source = """
start: expr+ NEWLINE? ENDMARKER
expr: NAME {PyTuple_New(-1)}
"""
grammar = parse_string(grammar_source, GrammarParser)
extension = generate_parser_c_extension(grammar, Path(self.tmp_path))
# PyTuple_New raises SystemError if an invalid argument was passed.
with self.assertRaises(SystemError):
extension.parse_string("a", mode=0)

225
Lib/test/test_peg_generator/test_first_sets.py Normal file
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import unittest
from test import test_tools
from typing import Dict, Set
test_tools.skip_if_missing('peg_generator')
with test_tools.imports_under_tool('peg_generator'):
from pegen.grammar_parser import GeneratedParser as GrammarParser
from pegen.testutil import parse_string
from pegen.first_sets import FirstSetCalculator
from pegen.grammar import Grammar
class TestFirstSets(unittest.TestCase):
def calculate_first_sets(self, grammar_source: str) -> Dict[str, Set[str]]:
grammar: Grammar = parse_string(grammar_source, GrammarParser)
return FirstSetCalculator(grammar.rules).calculate()
def test_alternatives(self) -> None:
grammar = """
start: expr NEWLINE? ENDMARKER
expr: A | B
A: 'a' | '-'
B: 'b' | '+'
"""
self.assertEqual(self.calculate_first_sets(grammar), {
"A": {"'a'", "'-'"},
"B": {"'+'", "'b'"},
"expr": {"'+'", "'a'", "'b'", "'-'"},
"start": {"'+'", "'a'", "'b'", "'-'"},
})
def test_optionals(self) -> None:
grammar = """
start: expr NEWLINE
expr: ['a'] ['b'] 'c'
"""
self.assertEqual(self.calculate_first_sets(grammar), {
"expr": {"'c'", "'a'", "'b'"},
"start": {"'c'", "'a'", "'b'"},
})
def test_repeat_with_separator(self) -> None:
grammar = """
start: ','.thing+ NEWLINE
thing: NUMBER
"""
self.assertEqual(self.calculate_first_sets(grammar), {"thing": {"NUMBER"}, "start": {"NUMBER"}})
def test_optional_operator(self) -> None:
grammar = """
start: sum NEWLINE
sum: (term)? 'b'
term: NUMBER
"""
self.assertEqual(self.calculate_first_sets(grammar), {
"term": {"NUMBER"},
"sum": {"NUMBER", "'b'"},
"start": {"'b'", "NUMBER"},
})
def test_optional_literal(self) -> None:
grammar = """
start: sum NEWLINE
sum: '+' ? term
term: NUMBER
"""
self.assertEqual(self.calculate_first_sets(grammar), {
"term": {"NUMBER"},
"sum": {"'+'", "NUMBER"},
"start": {"'+'", "NUMBER"},
})
def test_optional_after(self) -> None:
grammar = """
start: term NEWLINE
term: NUMBER ['+']
"""
self.assertEqual(self.calculate_first_sets(grammar), {"term": {"NUMBER"}, "start": {"NUMBER"}})
def test_optional_before(self) -> None:
grammar = """
start: term NEWLINE
term: ['+'] NUMBER
"""
self.assertEqual(self.calculate_first_sets(grammar), {"term": {"NUMBER", "'+'"}, "start": {"NUMBER", "'+'"}})
def test_repeat_0(self) -> None:
grammar = """
start: thing* "+" NEWLINE
thing: NUMBER
"""
self.assertEqual(self.calculate_first_sets(grammar), {"thing": {"NUMBER"}, "start": {'"+"', "NUMBER"}})
def test_repeat_0_with_group(self) -> None:
grammar = """
start: ('+' '-')* term NEWLINE
term: NUMBER
"""
self.assertEqual(self.calculate_first_sets(grammar), {"term": {"NUMBER"}, "start": {"'+'", "NUMBER"}})
def test_repeat_1(self) -> None:
grammar = """
start: thing+ '-' NEWLINE
thing: NUMBER
"""
self.assertEqual(self.calculate_first_sets(grammar), {"thing": {"NUMBER"}, "start": {"NUMBER"}})
def test_repeat_1_with_group(self) -> None:
grammar = """
start: ('+' term)+ term NEWLINE
term: NUMBER
"""
self.assertEqual(self.calculate_first_sets(grammar), {"term": {"NUMBER"}, "start": {"'+'"}})
def test_gather(self) -> None:
grammar = """
start: ','.thing+ NEWLINE
thing: NUMBER
"""
self.assertEqual(self.calculate_first_sets(grammar), {"thing": {"NUMBER"}, "start": {"NUMBER"}})
def test_positive_lookahead(self) -> None:
grammar = """
start: expr NEWLINE
expr: &'a' opt
opt: 'a' | 'b' | 'c'
"""
self.assertEqual(self.calculate_first_sets(grammar), {
"expr": {"'a'"},
"start": {"'a'"},
"opt": {"'b'", "'c'", "'a'"},
})
def test_negative_lookahead(self) -> None:
grammar = """
start: expr NEWLINE
expr: !'a' opt
opt: 'a' | 'b' | 'c'
"""
self.assertEqual(self.calculate_first_sets(grammar), {
"opt": {"'b'", "'a'", "'c'"},
"expr": {"'b'", "'c'"},
"start": {"'b'", "'c'"},
})
def test_left_recursion(self) -> None:
grammar = """
start: expr NEWLINE
expr: ('-' term | expr '+' term | term)
term: NUMBER
foo: 'foo'
bar: 'bar'
baz: 'baz'
"""
self.assertEqual(self.calculate_first_sets(grammar), {
"expr": {"NUMBER", "'-'"},
"term": {"NUMBER"},
"start": {"NUMBER", "'-'"},
"foo": {"'foo'"},
"bar": {"'bar'"},
"baz": {"'baz'"},
})
def test_advance_left_recursion(self) -> None:
grammar = """
start: NUMBER | sign start
sign: ['-']
"""
self.assertEqual(self.calculate_first_sets(grammar), {"sign": {"'-'", ""}, "start": {"'-'", "NUMBER"}})
def test_mutual_left_recursion(self) -> None:
grammar = """
start: foo 'E'
foo: bar 'A' | 'B'
bar: foo 'C' | 'D'
"""
self.assertEqual(self.calculate_first_sets(grammar), {
"foo": {"'D'", "'B'"},
"bar": {"'D'"},
"start": {"'D'", "'B'"},
})
def test_nasty_left_recursion(self) -> None:
# TODO: Validate this
grammar = """
start: target '='
target: maybe '+' | NAME
maybe: maybe '-' | target
"""
self.assertEqual(self.calculate_first_sets(grammar), {"maybe": set(), "target": {"NAME"}, "start": {"NAME"}})
def test_nullable_rule(self) -> None:
grammar = """
start: sign thing $
sign: ['-']
thing: NUMBER
"""
self.assertEqual(self.calculate_first_sets(grammar), {
"sign": {"", "'-'"},
"thing": {"NUMBER"},
"start": {"NUMBER", "'-'"},
})
def test_epsilon_production_in_start_rule(self) -> None:
grammar = """
start: ['-'] $
"""
self.assertEqual(self.calculate_first_sets(grammar), {"start": {"ENDMARKER", "'-'"}})
def test_multiple_nullable_rules(self) -> None:
grammar = """
start: sign thing other another $
sign: ['-']
thing: ['+']
other: '*'
another: '/'
"""
self.assertEqual(self.calculate_first_sets(grammar), {
"sign": {"", "'-'"},
"thing": {"'+'", ""},
"start": {"'+'", "'-'", "'*'"},
"other": {"'*'"},
"another": {"'/'"},
})

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Lib/test/test_peg_generator/test_pegen.py Normal file
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import io
import textwrap
import unittest
from test import test_tools
from typing import Dict, Any
from tokenize import TokenInfo, NAME, NEWLINE, NUMBER, OP
test_tools.skip_if_missing('peg_generator')
with test_tools.imports_under_tool('peg_generator'):
from pegen.grammar_parser import GeneratedParser as GrammarParser
from pegen.testutil import (
parse_string,
generate_parser,
make_parser
)
from pegen.grammar import GrammarVisitor, GrammarError, Grammar
from pegen.grammar_visualizer import ASTGrammarPrinter
from pegen.parser import Parser
from pegen.python_generator import PythonParserGenerator
class TestPegen(unittest.TestCase):
def test_parse_grammar(self) -> None:
grammar_source = """
start: sum NEWLINE
sum: t1=term '+' t2=term { action } | term
term: NUMBER
"""
expected = """
start: sum NEWLINE
sum: term '+' term | term
term: NUMBER
"""
grammar: Grammar = parse_string(grammar_source, GrammarParser)
rules = grammar.rules
self.assertEqual(str(grammar), textwrap.dedent(expected).strip())
# Check the str() and repr() of a few rules; AST nodes don't support ==.
self.assertEqual(str(rules["start"]), "start: sum NEWLINE")
self.assertEqual(str(rules["sum"]), "sum: term '+' term | term")
expected_repr = "Rule('term', None, Rhs([Alt([NamedItem(None, NameLeaf('NUMBER'))])]))"
self.assertEqual(repr(rules["term"]), expected_repr)
def test_long_rule_str(self) -> None:
grammar_source = """
start: zero | one | one zero | one one | one zero zero | one zero one | one one zero | one one one
"""
expected = """
start:
| zero
| one
| one zero
| one one
| one zero zero
| one zero one
| one one zero
| one one one
"""
grammar: Grammar = parse_string(grammar_source, GrammarParser)
self.assertEqual(str(grammar.rules["start"]), textwrap.dedent(expected).strip())
def test_typed_rules(self) -> None:
grammar = """
start[int]: sum NEWLINE
sum[int]: t1=term '+' t2=term { action } | term
term[int]: NUMBER
"""
rules = parse_string(grammar, GrammarParser).rules
# Check the str() and repr() of a few rules; AST nodes don't support ==.
self.assertEqual(str(rules["start"]), "start: sum NEWLINE")
self.assertEqual(str(rules["sum"]), "sum: term '+' term | term")
self.assertEqual(
repr(rules["term"]),
"Rule('term', 'int', Rhs([Alt([NamedItem(None, NameLeaf('NUMBER'))])]))"
)
def test_repeat_with_separator_rules(self) -> None:
grammar = """
start: ','.thing+ NEWLINE
thing: NUMBER
"""
rules = parse_string(grammar, GrammarParser).rules
self.assertEqual(str(rules["start"]), "start: ','.thing+ NEWLINE")
print(repr(rules["start"]))
self.assertTrue(repr(rules["start"]).startswith(
"Rule('start', None, Rhs([Alt([NamedItem(None, Gather(StringLeaf(\"','\"), NameLeaf('thing'"
))
self.assertEqual(str(rules["thing"]), "thing: NUMBER")
def test_expr_grammar(self) -> None:
grammar = """
start: sum NEWLINE
sum: term '+' term | term
term: NUMBER
"""
parser_class = make_parser(grammar)
node = parse_string("42\n", parser_class)
self.assertEqual(node, [
[[TokenInfo(NUMBER, string="42", start=(1, 0), end=(1, 2), line="42\n")]],
TokenInfo(NEWLINE, string="\n", start=(1, 2), end=(1, 3), line="42\n"),
])
def test_optional_operator(self) -> None:
grammar = """
start: sum NEWLINE
sum: term ('+' term)?
term: NUMBER
"""
parser_class = make_parser(grammar)
node = parse_string("1+2\n", parser_class)
self.assertEqual(node, [
[
[TokenInfo(NUMBER, string="1", start=(1, 0), end=(1, 1), line="1+2\n")],
[
TokenInfo(OP, string="+", start=(1, 1), end=(1, 2), line="1+2\n"),
[TokenInfo(NUMBER, string="2", start=(1, 2), end=(1, 3), line="1+2\n")],
],
],
TokenInfo(NEWLINE, string="\n", start=(1, 3), end=(1, 4), line="1+2\n"),
])
node = parse_string("1\n", parser_class)
self.assertEqual(node, [
[[TokenInfo(NUMBER, string="1", start=(1, 0), end=(1, 1), line="1\n")], None],
TokenInfo(NEWLINE, string="\n", start=(1, 1), end=(1, 2), line="1\n"),
])
def test_optional_literal(self) -> None:
grammar = """
start: sum NEWLINE
sum: term '+' ?
term: NUMBER
"""
parser_class = make_parser(grammar)
node = parse_string("1+\n", parser_class)
self.assertEqual(node, [
[
[TokenInfo(NUMBER, string="1", start=(1, 0), end=(1, 1), line="1+\n")],
TokenInfo(OP, string="+", start=(1, 1), end=(1, 2), line="1+\n"),
],
TokenInfo(NEWLINE, string="\n", start=(1, 2), end=(1, 3), line="1+\n"),
])
node = parse_string("1\n", parser_class)
self.assertEqual(node, [
[[TokenInfo(NUMBER, string="1", start=(1, 0), end=(1, 1), line="1\n")], None],
TokenInfo(NEWLINE, string="\n", start=(1, 1), end=(1, 2), line="1\n"),
])
def test_alt_optional_operator(self) -> None:
grammar = """
start: sum NEWLINE
sum: term ['+' term]
term: NUMBER
"""
parser_class = make_parser(grammar)
node = parse_string("1 + 2\n", parser_class)
self.assertEqual(node, [
[
[TokenInfo(NUMBER, string="1", start=(1, 0), end=(1, 1), line="1 + 2\n")],
[
TokenInfo(OP, string="+", start=(1, 2), end=(1, 3), line="1 + 2\n"),
[TokenInfo(NUMBER, string="2", start=(1, 4), end=(1, 5), line="1 + 2\n")],
],
],
TokenInfo(NEWLINE, string="\n", start=(1, 5), end=(1, 6), line="1 + 2\n"),
])
node = parse_string("1\n", parser_class)
self.assertEqual(node, [
[[TokenInfo(NUMBER, string="1", start=(1, 0), end=(1, 1), line="1\n")], None],
TokenInfo(NEWLINE, string="\n", start=(1, 1), end=(1, 2), line="1\n"),
])
def test_repeat_0_simple(self) -> None:
grammar = """
start: thing thing* NEWLINE
thing: NUMBER
"""
parser_class = make_parser(grammar)
node = parse_string("1 2 3\n", parser_class)
self.assertEqual(node, [
[TokenInfo(NUMBER, string="1", start=(1, 0), end=(1, 1), line="1 2 3\n")],
[
[[TokenInfo(NUMBER, string="2", start=(1, 2), end=(1, 3), line="1 2 3\n")]],
[[TokenInfo(NUMBER, string="3", start=(1, 4), end=(1, 5), line="1 2 3\n")]],
],
TokenInfo(NEWLINE, string="\n", start=(1, 5), end=(1, 6), line="1 2 3\n"),
])
node = parse_string("1\n", parser_class)
self.assertEqual(node, [
[TokenInfo(NUMBER, string="1", start=(1, 0), end=(1, 1), line="1\n")],
[],
TokenInfo(NEWLINE, string="\n", start=(1, 1), end=(1, 2), line="1\n"),
])
def test_repeat_0_complex(self) -> None:
grammar = """
start: term ('+' term)* NEWLINE
term: NUMBER
"""
parser_class = make_parser(grammar)
node = parse_string("1 + 2 + 3\n", parser_class)
self.assertEqual(node, [
[TokenInfo(NUMBER, string="1", start=(1, 0), end=(1, 1), line="1 + 2 + 3\n")],
[
[
[
TokenInfo(OP, string="+", start=(1, 2), end=(1, 3), line="1 + 2 + 3\n"),
[TokenInfo(NUMBER, string="2", start=(1, 4), end=(1, 5), line="1 + 2 + 3\n")],
]
],
[
[
TokenInfo(OP, string="+", start=(1, 6), end=(1, 7), line="1 + 2 + 3\n"),
[TokenInfo(NUMBER, string="3", start=(1, 8), end=(1, 9), line="1 + 2 + 3\n")],
]
],
],
TokenInfo(NEWLINE, string="\n", start=(1, 9), end=(1, 10), line="1 + 2 + 3\n"),
])
def test_repeat_1_simple(self) -> None:
grammar = """
start: thing thing+ NEWLINE
thing: NUMBER
"""
parser_class = make_parser(grammar)
node = parse_string("1 2 3\n", parser_class)
self.assertEqual(node, [
[TokenInfo(NUMBER, string="1", start=(1, 0), end=(1, 1), line="1 2 3\n")],
[
[[TokenInfo(NUMBER, string="2", start=(1, 2), end=(1, 3), line="1 2 3\n")]],
[[TokenInfo(NUMBER, string="3", start=(1, 4), end=(1, 5), line="1 2 3\n")]],
],
TokenInfo(NEWLINE, string="\n", start=(1, 5), end=(1, 6), line="1 2 3\n"),
])
with self.assertRaises(SyntaxError):
parse_string("1\n", parser_class)
def test_repeat_1_complex(self) -> None:
grammar = """
start: term ('+' term)+ NEWLINE
term: NUMBER
"""
parser_class = make_parser(grammar)
node = parse_string("1 + 2 + 3\n", parser_class)
self.assertEqual(node, [
[TokenInfo(NUMBER, string="1", start=(1, 0), end=(1, 1), line="1 + 2 + 3\n")],
[
[
[
TokenInfo(OP, string="+", start=(1, 2), end=(1, 3), line="1 + 2 + 3\n"),
[TokenInfo(NUMBER, string="2", start=(1, 4), end=(1, 5), line="1 + 2 + 3\n")],
]
],
[
[
TokenInfo(OP, string="+", start=(1, 6), end=(1, 7), line="1 + 2 + 3\n"),
[TokenInfo(NUMBER, string="3", start=(1, 8), end=(1, 9), line="1 + 2 + 3\n")],
]
],
],
TokenInfo(NEWLINE, string="\n", start=(1, 9), end=(1, 10), line="1 + 2 + 3\n"),
])
with self.assertRaises(SyntaxError):
parse_string("1\n", parser_class)
def test_repeat_with_sep_simple(self) -> None:
grammar = """
start: ','.thing+ NEWLINE
thing: NUMBER
"""
parser_class = make_parser(grammar)
node = parse_string("1, 2, 3\n", parser_class)
self.assertEqual(node, [
[
[TokenInfo(NUMBER, string="1", start=(1, 0), end=(1, 1), line="1, 2, 3\n")],
[TokenInfo(NUMBER, string="2", start=(1, 3), end=(1, 4), line="1, 2, 3\n")],
[TokenInfo(NUMBER, string="3", start=(1, 6), end=(1, 7), line="1, 2, 3\n")],
],
TokenInfo(NEWLINE, string="\n", start=(1, 7), end=(1, 8), line="1, 2, 3\n"),
])
def test_left_recursive(self) -> None:
grammar_source = """
start: expr NEWLINE
expr: ('-' term | expr '+' term | term)
term: NUMBER
foo: NAME+
bar: NAME*
baz: NAME?
"""
grammar: Grammar = parse_string(grammar_source, GrammarParser)
parser_class = generate_parser(grammar)
rules = grammar.rules
self.assertFalse(rules["start"].left_recursive)
self.assertTrue(rules["expr"].left_recursive)
self.assertFalse(rules["term"].left_recursive)
self.assertFalse(rules["foo"].left_recursive)
self.assertFalse(rules["bar"].left_recursive)
self.assertFalse(rules["baz"].left_recursive)
node = parse_string("1 + 2 + 3\n", parser_class)
self.assertEqual(node, [
[
[
[[TokenInfo(NUMBER, string="1", start=(1, 0), end=(1, 1), line="1 + 2 + 3\n")]],
TokenInfo(OP, string="+", start=(1, 2), end=(1, 3), line="1 + 2 + 3\n"),
[TokenInfo(NUMBER, string="2", start=(1, 4), end=(1, 5), line="1 + 2 + 3\n")],
],
TokenInfo(OP, string="+", start=(1, 6), end=(1, 7), line="1 + 2 + 3\n"),
[TokenInfo(NUMBER, string="3", start=(1, 8), end=(1, 9), line="1 + 2 + 3\n")],
],
TokenInfo(NEWLINE, string="\n", start=(1, 9), end=(1, 10), line="1 + 2 + 3\n"),
])
def test_python_expr(self) -> None:
grammar = """
start: expr NEWLINE? $ { ast.Expression(expr, lineno=1, col_offset=0) }
expr: ( expr '+' term { ast.BinOp(expr, ast.Add(), term, lineno=expr.lineno, col_offset=expr.col_offset, end_lineno=term.end_lineno, end_col_offset=term.end_col_offset) }
| expr '-' term { ast.BinOp(expr, ast.Sub(), term, lineno=expr.lineno, col_offset=expr.col_offset, end_lineno=term.end_lineno, end_col_offset=term.end_col_offset) }
| term { term }
)
term: ( l=term '*' r=factor { ast.BinOp(l, ast.Mult(), r, lineno=l.lineno, col_offset=l.col_offset, end_lineno=r.end_lineno, end_col_offset=r.end_col_offset) }
| l=term '/' r=factor { ast.BinOp(l, ast.Div(), r, lineno=l.lineno, col_offset=l.col_offset, end_lineno=r.end_lineno, end_col_offset=r.end_col_offset) }
| factor { factor }
)
factor: ( '(' expr ')' { expr }
| atom { atom }
)
atom: ( n=NAME { ast.Name(id=n.string, ctx=ast.Load(), lineno=n.start[0], col_offset=n.start[1], end_lineno=n.end[0], end_col_offset=n.end[1]) }
| n=NUMBER { ast.Constant(value=ast.literal_eval(n.string), lineno=n.start[0], col_offset=n.start[1], end_lineno=n.end[0], end_col_offset=n.end[1]) }
)
"""
parser_class = make_parser(grammar)
node = parse_string("(1 + 2*3 + 5)/(6 - 2)\n", parser_class)
code = compile(node, "", "eval")
val = eval(code)
self.assertEqual(val, 3.0)
def test_nullable(self) -> None:
grammar_source = """
start: sign NUMBER
sign: ['-' | '+']
"""
grammar: Grammar = parse_string(grammar_source, GrammarParser)
out = io.StringIO()
genr = PythonParserGenerator(grammar, out)
rules = grammar.rules
self.assertFalse(rules["start"].nullable) # Not None!
self.assertTrue(rules["sign"].nullable)
def test_advanced_left_recursive(self) -> None:
grammar_source = """
start: NUMBER | sign start
sign: ['-']
"""
grammar: Grammar = parse_string(grammar_source, GrammarParser)
out = io.StringIO()
genr = PythonParserGenerator(grammar, out)
rules = grammar.rules
self.assertFalse(rules["start"].nullable) # Not None!
self.assertTrue(rules["sign"].nullable)
self.assertTrue(rules["start"].left_recursive)
self.assertFalse(rules["sign"].left_recursive)
def test_mutually_left_recursive(self) -> None:
grammar_source = """
start: foo 'E'
foo: bar 'A' | 'B'
bar: foo 'C' | 'D'
"""
grammar: Grammar = parse_string(grammar_source, GrammarParser)
out = io.StringIO()
genr = PythonParserGenerator(grammar, out)
rules = grammar.rules
self.assertFalse(rules["start"].left_recursive)
self.assertTrue(rules["foo"].left_recursive)
self.assertTrue(rules["bar"].left_recursive)
genr.generate("<string>")
ns: Dict[str, Any] = {}
exec(out.getvalue(), ns)
parser_class: Type[Parser] = ns["GeneratedParser"]
node = parse_string("D A C A E", parser_class)
self.assertEqual(node, [
[
[
[
[TokenInfo(type=NAME, string="D", start=(1, 0), end=(1, 1), line="D A C A E")],
TokenInfo(type=NAME, string="A", start=(1, 2), end=(1, 3), line="D A C A E"),
],
TokenInfo(type=NAME, string="C", start=(1, 4), end=(1, 5), line="D A C A E"),
],
TokenInfo(type=NAME, string="A", start=(1, 6), end=(1, 7), line="D A C A E"),
],
TokenInfo(type=NAME, string="E", start=(1, 8), end=(1, 9), line="D A C A E"),
])
node = parse_string("B C A E", parser_class)
self.assertIsNotNone(node)
self.assertEqual(node, [
[
[
[TokenInfo(type=NAME, string="B", start=(1, 0), end=(1, 1), line="B C A E")],
TokenInfo(type=NAME, string="C", start=(1, 2), end=(1, 3), line="B C A E"),
],
TokenInfo(type=NAME, string="A", start=(1, 4), end=(1, 5), line="B C A E"),
],
TokenInfo(type=NAME, string="E", start=(1, 6), end=(1, 7), line="B C A E"),
])
def test_nasty_mutually_left_recursive(self) -> None:
# This grammar does not recognize 'x - + =', much to my chagrin.
# But that's the way PEG works.
# [Breathlessly]
# The problem is that the toplevel target call
# recurses into maybe, which recognizes 'x - +',
# and then the toplevel target looks for another '+',
# which fails, so it retreats to NAME,
# which succeeds, so we end up just recognizing 'x',
# and then start fails because there's no '=' after that.
grammar_source = """
start: target '='
target: maybe '+' | NAME
maybe: maybe '-' | target
"""
grammar: Grammar = parse_string(grammar_source, GrammarParser)
out = io.StringIO()
genr = PythonParserGenerator(grammar, out)
genr.generate("<string>")
ns: Dict[str, Any] = {}
exec(out.getvalue(), ns)
parser_class = ns["GeneratedParser"]
with self.assertRaises(SyntaxError):
parse_string("x - + =", parser_class)
def test_lookahead(self) -> None:
grammar = """
start: (expr_stmt | assign_stmt) &'.'
expr_stmt: !(target '=') expr
assign_stmt: target '=' expr
expr: term ('+' term)*
target: NAME
term: NUMBER
"""
parser_class = make_parser(grammar)
node = parse_string("foo = 12 + 12 .", parser_class)
self.assertEqual(node, [
[
[
[TokenInfo(NAME, string="foo", start=(1, 0), end=(1, 3), line="foo = 12 + 12 .")],
TokenInfo(OP, string="=", start=(1, 4), end=(1, 5), line="foo = 12 + 12 ."),
[
[
TokenInfo(
NUMBER, string="12", start=(1, 6), end=(1, 8), line="foo = 12 + 12 ."
)
],
[
[
[
TokenInfo(
OP,
string="+",
start=(1, 9),
end=(1, 10),
line="foo = 12 + 12 .",
),
[
TokenInfo(
NUMBER,
string="12",
start=(1, 11),
end=(1, 13),
line="foo = 12 + 12 .",
)
],
]
]
],
],
]
]
])
def test_named_lookahead_error(self) -> None:
grammar = """
start: foo=!'x' NAME
"""
with self.assertRaises(SyntaxError):
make_parser(grammar)
def test_start_leader(self) -> None:
grammar = """
start: attr | NAME
attr: start '.' NAME
"""
# Would assert False without a special case in compute_left_recursives().
make_parser(grammar)
def test_left_recursion_too_complex(self) -> None:
grammar = """
start: foo
foo: bar '+' | baz '+' | '+'
bar: baz '-' | foo '-' | '-'
baz: foo '*' | bar '*' | '*'
"""
with self.assertRaises(ValueError) as errinfo:
make_parser(grammar)
self.assertTrue("no leader" in str(errinfo.exception.value))
def test_cut(self) -> None:
grammar = """
start: '(' ~ expr ')'
expr: NUMBER
"""
parser_class = make_parser(grammar)
node = parse_string("(1)", parser_class, verbose=True)
self.assertEqual(node, [
TokenInfo(OP, string="(", start=(1, 0), end=(1, 1), line="(1)"),
[TokenInfo(NUMBER, string="1", start=(1, 1), end=(1, 2), line="(1)")],
TokenInfo(OP, string=")", start=(1, 2), end=(1, 3), line="(1)"),
])
def test_dangling_reference(self) -> None:
grammar = """
start: foo ENDMARKER
foo: bar NAME
"""
with self.assertRaises(GrammarError):
parser_class = make_parser(grammar)
def test_bad_token_reference(self) -> None:
grammar = """
start: foo
foo: NAMEE
"""
with self.assertRaises(GrammarError):
parser_class = make_parser(grammar)
def test_missing_start(self) -> None:
grammar = """
foo: NAME
"""
with self.assertRaises(GrammarError):
parser_class = make_parser(grammar)
class TestGrammarVisitor:
class Visitor(GrammarVisitor):
def __init__(self) -> None:
self.n_nodes = 0
def visit(self, node: Any, *args: Any, **kwargs: Any) -> None:
self.n_nodes += 1
super().visit(node, *args, **kwargs)
def test_parse_trivial_grammar(self) -> None:
grammar = """
start: 'a'
"""
rules = parse_string(grammar, GrammarParser)
visitor = self.Visitor()
visitor.visit(rules)
self.assertEqual(visitor.n_nodes, 6)
def test_parse_or_grammar(self) -> None:
grammar = """
start: rule
rule: 'a' | 'b'
"""
rules = parse_string(grammar, GrammarParser)
visitor = self.Visitor()
visitor.visit(rules)
# Grammar/Rule/Rhs/Alt/NamedItem/NameLeaf -> 6
# Rule/Rhs/ -> 2
# Alt/NamedItem/StringLeaf -> 3
# Alt/NamedItem/StringLeaf -> 3
self.assertEqual(visitor.n_nodes, 14)
def test_parse_repeat1_grammar(self) -> None:
grammar = """
start: 'a'+
"""
rules = parse_string(grammar, GrammarParser)
visitor = self.Visitor()
visitor.visit(rules)
# Grammar/Rule/Rhs/Alt/NamedItem/Repeat1/StringLeaf -> 6
self.assertEqual(visitor.n_nodes, 7)
def test_parse_repeat0_grammar(self) -> None:
grammar = """
start: 'a'*
"""
rules = parse_string(grammar, GrammarParser)
visitor = self.Visitor()
visitor.visit(rules)
# Grammar/Rule/Rhs/Alt/NamedItem/Repeat0/StringLeaf -> 6
self.assertEqual(visitor.n_nodes, 7)
def test_parse_optional_grammar(self) -> None:
grammar = """
start: 'a' ['b']
"""
rules = parse_string(grammar, GrammarParser)
visitor = self.Visitor()
visitor.visit(rules)
# Grammar/Rule/Rhs/Alt/NamedItem/StringLeaf -> 6
# NamedItem/Opt/Rhs/Alt/NamedItem/Stringleaf -> 6
self.assertEqual(visitor.n_nodes, 12)
class TestGrammarVisualizer(unittest.TestCase):
def test_simple_rule(self) -> None:
grammar = """
start: 'a' 'b'
"""
rules = parse_string(grammar, GrammarParser)
printer = ASTGrammarPrinter()
lines: List[str] = []
printer.print_grammar_ast(rules, printer=lines.append)
output = "\n".join(lines)
expected_output = textwrap.dedent(
"""\
└──Rule
└──Rhs
└──Alt
├──NamedItem
│ └──StringLeaf("'a'")
└──NamedItem
└──StringLeaf("'b'")
"""
)
self.assertEqual(output, expected_output)
def test_multiple_rules(self) -> None:
grammar = """
start: a b
a: 'a'
b: 'b'
"""
rules = parse_string(grammar, GrammarParser)
printer = ASTGrammarPrinter()
lines: List[str] = []
printer.print_grammar_ast(rules, printer=lines.append)
output = "\n".join(lines)
expected_output = textwrap.dedent(
"""\
└──Rule
└──Rhs
└──Alt
├──NamedItem
│ └──NameLeaf('a')
└──NamedItem
└──NameLeaf('b')
└──Rule
└──Rhs
└──Alt
└──NamedItem
└──StringLeaf("'a'")
└──Rule
└──Rhs
└──Alt
└──NamedItem
└──StringLeaf("'b'")
"""
)
self.assertEqual(output, expected_output)
def test_deep_nested_rule(self) -> None:
grammar = """
start: 'a' ['b'['c'['d']]]
"""
rules = parse_string(grammar, GrammarParser)
printer = ASTGrammarPrinter()
lines: List[str] = []
printer.print_grammar_ast(rules, printer=lines.append)
output = "\n".join(lines)
print()
print(output)
expected_output = textwrap.dedent(
"""\
└──Rule
└──Rhs
└──Alt
├──NamedItem
│ └──StringLeaf("'a'")
└──NamedItem
└──Opt
└──Rhs
└──Alt
├──NamedItem
│ └──StringLeaf("'b'")
└──NamedItem
└──Opt
└──Rhs
└──Alt
├──NamedItem
│ └──StringLeaf("'c'")
└──NamedItem
└──Opt
└──Rhs
└──Alt
└──NamedItem
└──StringLeaf("'d'")
"""
)
self.assertEqual(output, expected_output)

764
Lib/test/test_peg_parser.py Normal file
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@ -0,0 +1,764 @@
import ast
import os
import sys
import _peg_parser as peg_parser
import unittest
from pathlib import PurePath
from typing import Any, Union, Iterable, Tuple
from textwrap import dedent
TEST_CASES = [
('annotated_assignment', 'x: int = 42'),
('annotated_assignment_with_tuple', 'x: tuple = 1, 2'),
('annotated_assignment_with_parens', '(paren): int = 3+2'),
('annotated_assignment_with_yield', 'x: int = yield 42'),
('annotated_no_assignment', 'x: int'),
('annotation_with_multiple_parens', '((parens)): int'),
('annotation_with_parens', '(parens): int'),
('annotated_assignment_with_attr', 'a.b: int'),
('annotated_assignment_with_subscript', 'a[b]: int'),
('annotated_assignment_with_attr_and_parens', '(a.b): int'),
('annotated_assignment_with_subscript_and_parens', '(a[b]): int'),
('assert', 'assert a'),
('assert_message', 'assert a, b'),
('assignment_false', 'a = False'),
('assignment_none', 'a = None'),
('assignment_true', 'a = True'),
('assignment_paren', '(a) = 42'),
('assignment_paren_multiple', '(a, b) = (0, 1)'),
('asyncfor',
'''
async for i in a:
pass
'''),
('attribute_call', 'a.b()'),
('attribute_multiple_names', 'abcd.efg.hij'),
('attribute_simple', 'a.b'),
('attributes_subscript', 'a.b[0]'),
('augmented_assignment', 'x += 42'),
('binop_add', '1 + 1'),
('binop_add_multiple', '1 + 1 + 1 + 1'),
('binop_all', '1 + 2 * 5 + 3 ** 2 - -3'),
('binop_boolop_comp', '1 + 1 == 2 or 1 + 1 == 3 and not b'),
('boolop_or', 'a or b'),
('boolop_or_multiple', 'a or b or c'),
('class_def_bases',
'''
class C(A, B):
pass
'''),
('class_def_decorators',
'''
@a
class C:
pass
'''),
('class_def_decorator_with_expression',
'''
@lambda x: 42
class C:
pass
'''),
('class_def_decorator_with_expression_and_walrus',
'''
@x:=lambda x: 42
class C:
pass
'''),
('class_def_keywords',
'''
class C(keyword=a+b, **c):
pass
'''),
('class_def_mixed',
'''
class C(A, B, keyword=0, **a):
pass
'''),
('class_def_simple',
'''
class C:
pass
'''),
('class_def_starred_and_kwarg',
'''
class C(A, B, *x, **y):
pass
'''),
('class_def_starred_in_kwargs',
'''
class C(A, x=2, *[B, C], y=3):
pass
'''),
('call_attribute', 'f().b'),
('call_genexp', 'f(i for i in a)'),
('call_mixed_args', 'f(a, b, *c, **d)'),
('call_mixed_args_named', 'f(a, b, *c, d=4, **v)'),
('call_one_arg', 'f(a)'),
('call_posarg_genexp', 'f(a, (i for i in a))'),
('call_simple', 'f()'),
('call_subscript', 'f()[0]'),
('comp', 'a == b'),
('comp_multiple', 'a == b == c'),
('comp_paren_end', 'a == (b-1)'),
('comp_paren_start', '(a-1) == b'),
('decorator',
'''
@a
def f():
pass
'''),
('decorator_async',
'''
@a
async def d():
pass
'''),
('decorator_with_expression',
'''
@lambda x: 42
def f():
pass
'''),
('decorator_with_expression_and_walrus',
'''
@x:=lambda x: 42
def f():
pass
'''),
('del_attribute', 'del a.b'),
('del_call_attribute', 'del a().c'),
('del_call_genexp_attribute', 'del a(i for i in b).c'),
('del_empty', 'del()'),
('del_list', 'del a, [b, c]'),
('del_mixed', 'del a[0].b().c'),
('del_multiple', 'del a, b'),
('del_multiple_calls_attribute', 'del a()().b'),
('del_paren', 'del(a,b)'),
('del_paren_single_target', 'del(a)'),
('del_subscript_attribute', 'del a[0].b'),
('del_tuple', 'del a, (b, c)'),
('delete', 'del a'),
('dict',
'''
{
a: 1,
b: 2,
c: 3
}
'''),
('dict_comp', '{x:1 for x in a}'),
('dict_comp_if', '{x:1+2 for x in a if b}'),
('dict_empty', '{}'),
('for',
'''
for i in a:
pass
'''),
('for_else',
'''
for i in a:
pass
else:
pass
'''),
('for_star_target_in_paren', 'for (a) in b: pass'),
('for_star_targets_attribute', 'for a.b in c: pass'),
('for_star_targets_call_attribute', 'for a().c in b: pass'),
('for_star_targets_empty', 'for () in a: pass'),
('for_star_targets_mixed', 'for a[0].b().c in d: pass'),
('for_star_targets_mixed_starred',
'''
for a, *b, (c, d) in e:
pass
'''),
('for_star_targets_multiple', 'for a, b in c: pass'),
('for_star_targets_nested_starred', 'for *[*a] in b: pass'),
('for_star_targets_starred', 'for *a in b: pass'),
('for_star_targets_subscript_attribute', 'for a[0].b in c: pass'),
('for_star_targets_trailing_comma',
'''
for a, (b, c), in d:
pass
'''),
('for_star_targets_tuple', 'for a, (b, c) in d: pass'),
('for_underscore',
'''
for _ in a:
pass
'''),
('function_return_type',
'''
def f() -> Any:
pass
'''),
('f-string_slice', "f'{x[2]}'"),
('f-string_slice_upper', "f'{x[2:3]}'"),
('f-string_slice_step', "f'{x[2:3:-2]}'"),
('f-string_constant', "f'{42}'"),
('f-string_boolop', "f'{x and y}'"),
('f-string_named_expr', "f'{(x:=42)}'"),
('f-string_binop', "f'{x+y}'"),
('f-string_unaryop', "f'{not x}'"),
('f-string_lambda', "f'{(lambda x, /, y, y2=42 , *z, k1, k2=34, **k3: 42)}'"),
('f-string_lambda_call', "f'{(lambda: 2)(2)}'"),
('f-string_ifexpr', "f'{x if y else z}'"),
('f-string_dict', "f'{ {2:34, 3:34} }'"),
('f-string_set', "f'{ {2,-45} }'"),
('f-string_list', "f'{ [2,-45] }'"),
('f-string_tuple', "f'{ (2,-45) }'"),
('f-string_listcomp', "f'{[x for x in y if z]}'"),
('f-string_setcomp', "f'{ {x for x in y if z} }'"),
('f-string_dictcomp', "f'{ {x:x for x in y if z} }'"),
('f-string_genexpr', "f'{ (x for x in y if z) }'"),
('f-string_yield', "f'{ (yield x) }'"),
('f-string_yieldfrom', "f'{ (yield from x) }'"),
('f-string_await', "f'{ await x }'"),
('f-string_compare', "f'{ x == y }'"),
('f-string_call', "f'{ f(x,y,z) }'"),
('f-string_attribute', "f'{ f.x.y.z }'"),
('f-string_starred', "f'{ *x, }'"),
('f-string_doublestarred', "f'{ {**x} }'"),
('f-string_escape_brace', "f'{{Escape'"),
('f-string_escape_closing_brace', "f'Escape}}'"),
('f-string_repr', "f'{a!r}'"),
('f-string_str', "f'{a!s}'"),
('f-string_ascii', "f'{a!a}'"),
('f-string_debug', "f'{a=}'"),
('f-string_padding', "f'{a:03d}'"),
('f-string_multiline',
"""
f'''
{hello}
'''
"""),
('f-string_multiline_in_expr',
"""
f'''
{
hello
}
'''
"""),
('f-string_multiline_in_call',
"""
f'''
{f(
a, b, c
)}
'''
"""),
('global', 'global a, b'),
('group', '(yield a)'),
('if_elif',
'''
if a:
pass
elif b:
pass
'''),
('if_elif_elif',
'''
if a:
pass
elif b:
pass
elif c:
pass
'''),
('if_elif_else',
'''
if a:
pass
elif b:
pass
else:
pass
'''),
('if_else',
'''
if a:
pass
else:
pass
'''),
('if_simple', 'if a: pass'),
('import', 'import a'),
('import_alias', 'import a as b'),
('import_dotted', 'import a.b'),
('import_dotted_alias', 'import a.b as c'),
('import_dotted_multichar', 'import ab.cd'),
('import_from', 'from a import b'),
('import_from_alias', 'from a import b as c'),
('import_from_dotted', 'from a.b import c'),
('import_from_dotted_alias', 'from a.b import c as d'),
('import_from_multiple_aliases', 'from a import b as c, d as e'),
('import_from_one_dot', 'from .a import b'),
('import_from_one_dot_alias', 'from .a import b as c'),
('import_from_star', 'from a import *'),
('import_from_three_dots', 'from ...a import b'),
('import_from_trailing_comma', 'from a import (b,)'),
('kwarg',
'''
def f(**a):
pass
'''),
('kwonly_args',
'''
def f(*, a, b):
pass
'''),
('kwonly_args_with_default',
'''
def f(*, a=2, b):
pass
'''),
('lambda_kwarg', 'lambda **a: 42'),
('lambda_kwonly_args', 'lambda *, a, b: 42'),
('lambda_kwonly_args_with_default', 'lambda *, a=2, b: 42'),
('lambda_mixed_args', 'lambda a, /, b, *, c: 42'),
('lambda_mixed_args_with_default', 'lambda a, b=2, /, c=3, *e, f, **g: 42'),
('lambda_no_args', 'lambda: 42'),
('lambda_pos_args', 'lambda a,b: 42'),
('lambda_pos_args_with_default', 'lambda a, b=2: 42'),
('lambda_pos_only_args', 'lambda a, /: 42'),
('lambda_pos_only_args_with_default', 'lambda a=0, /: 42'),
('lambda_pos_posonly_args', 'lambda a, b, /, c, d: 42'),
('lambda_pos_posonly_args_with_default', 'lambda a, b=0, /, c=2: 42'),
('lambda_vararg', 'lambda *a: 42'),
('lambda_vararg_kwonly_args', 'lambda *a, b: 42'),
('list', '[1, 2, a]'),
('list_comp', '[i for i in a]'),
('list_comp_if', '[i for i in a if b]'),
('list_trailing_comma', '[1+2, a, 3+4,]'),
('mixed_args',
'''
def f(a, /, b, *, c):
pass
'''),
('mixed_args_with_default',
'''
def f(a, b=2, /, c=3, *e, f, **g):
pass
'''),
('multipart_string_bytes', 'b"Hola" b"Hello" b"Bye"'),
('multipart_string_triple', '"""Something here""" "and now"'),
('multipart_string_different_prefixes', 'u"Something" "Other thing" r"last thing"'),
('multiple_assignments', 'x = y = z = 42'),
('multiple_assignments_with_yield', 'x = y = z = yield 42'),
('multiple_pass',
'''
pass; pass
pass
'''),
('namedexpr', '(x := [1, 2, 3])'),
('namedexpr_false', '(x := False)'),
('namedexpr_none', '(x := None)'),
('namedexpr_true', '(x := True)'),
('nonlocal', 'nonlocal a, b'),
('number_complex', '-2.234+1j'),
('number_float', '-34.2333'),
('number_imaginary_literal', '1.1234j'),
('number_integer', '-234'),
('number_underscores', '1_234_567'),
('pass', 'pass'),
('pos_args',
'''
def f(a, b):
pass
'''),
('pos_args_with_default',
'''
def f(a, b=2):
pass
'''),
('pos_only_args',
'''
def f(a, /):
pass
'''),
('pos_only_args_with_default',
'''
def f(a=0, /):
pass
'''),
('pos_posonly_args',
'''
def f(a, b, /, c, d):
pass
'''),
('pos_posonly_args_with_default',
'''
def f(a, b=0, /, c=2):
pass
'''),
('primary_mixed', 'a.b.c().d[0]'),
('raise', 'raise'),
('raise_ellipsis', 'raise ...'),
('raise_expr', 'raise a'),
('raise_from', 'raise a from b'),
('return', 'return'),
('return_expr', 'return a'),
('set', '{1, 2+4, 3+5}'),
('set_comp', '{i for i in a}'),
('set_trailing_comma', '{1, 2, 3,}'),
('simple_assignment', 'x = 42'),
('simple_assignment_with_yield', 'x = yield 42'),
('string_bytes', 'b"hello"'),
('string_concatenation_bytes', 'b"hello" b"world"'),
('string_concatenation_simple', '"abcd" "efgh"'),
('string_format_simple', 'f"hello"'),
('string_format_with_formatted_value', 'f"hello {world}"'),
('string_simple', '"hello"'),
('string_unicode', 'u"hello"'),
('subscript_attribute', 'a[0].b'),
('subscript_call', 'a[b]()'),
('subscript_multiple_slices', 'a[0:a:2, 1]'),
('subscript_simple', 'a[0]'),
('subscript_single_element_tuple', 'a[0,]'),
('subscript_trailing_comma', 'a[0, 1, 2,]'),
('subscript_tuple', 'a[0, 1, 2]'),
('subscript_whole_slice', 'a[0+1:b:c]'),
('try_except',
'''
try:
pass
except:
pass
'''),
('try_except_else',
'''
try:
pass
except:
pass
else:
pass
'''),
('try_except_else_finally',
'''
try:
pass
except:
pass
else:
pass
finally:
pass
'''),
('try_except_expr',
'''
try:
pass
except a:
pass
'''),
('try_except_expr_target',
'''
try:
pass
except a as b:
pass
'''),
('try_except_finally',
'''
try:
pass
except:
pass
finally:
pass
'''),
('try_finally',
'''
try:
pass
finally:
pass
'''),
('unpacking_binop', '[*([1, 2, 3] + [3, 4, 5])]'),
('unpacking_call', '[*b()]'),
('unpacking_compare', '[*(x < y)]'),
('unpacking_constant', '[*3]'),
('unpacking_dict', '[*{1: 2, 3: 4}]'),
('unpacking_dict_comprehension', '[*{x:y for x,y in z}]'),
('unpacking_ifexpr', '[*([1, 2, 3] if x else y)]'),
('unpacking_list', '[*[1,2,3]]'),
('unpacking_list_comprehension', '[*[x for x in y]]'),
('unpacking_namedexpr', '[*(x:=[1, 2, 3])]'),
('unpacking_set', '[*{1,2,3}]'),
('unpacking_set_comprehension', '[*{x for x in y}]'),
('unpacking_string', '[*"myvalue"]'),
('unpacking_tuple', '[*(1,2,3)]'),
('unpacking_unaryop', '[*(not [1, 2, 3])]'),
('unpacking_yield', '[*(yield 42)]'),
('unpacking_yieldfrom', '[*(yield from x)]'),
('tuple', '(1, 2, 3)'),
('vararg',
'''
def f(*a):
pass
'''),
('vararg_kwonly_args',
'''
def f(*a, b):
pass
'''),
('while',
'''
while a:
pass
'''),
('while_else',
'''
while a:
pass
else:
pass
'''),
('with',
'''
with a:
pass
'''),
('with_as',
'''
with a as b:
pass
'''),
('with_as_paren',
'''
with a as (b):
pass
'''),
('with_as_empty', 'with a as (): pass'),
('with_list_recursive',
'''
with a as [x, [y, z]]:
pass
'''),
('with_tuple_recursive',
'''
with a as ((x, y), z):
pass
'''),
('with_tuple_target',
'''
with a as (x, y):
pass
'''),
('yield', 'yield'),
('yield_expr', 'yield a'),
('yield_from', 'yield from a'),
]
FAIL_TEST_CASES = [
("annotation_multiple_targets", "(a, b): int = 42"),
("annotation_nested_tuple", "((a, b)): int"),
("annotation_list", "[a]: int"),
("annotation_lambda", "lambda: int = 42"),
("annotation_tuple", "(a,): int"),
("annotation_tuple_without_paren", "a,: int"),
("assignment_keyword", "a = if"),
("comprehension_lambda", "(a for a in lambda: b)"),
("comprehension_else", "(a for a in b if c else d"),
("del_call", "del a()"),
("del_call_genexp", "del a(i for i in b)"),
("del_subscript_call", "del a[b]()"),
("del_attribute_call", "del a.b()"),
("del_mixed_call", "del a[0].b().c.d()"),
("for_star_targets_call", "for a() in b: pass"),
("for_star_targets_subscript_call", "for a[b]() in c: pass"),
("for_star_targets_attribute_call", "for a.b() in c: pass"),
("for_star_targets_mixed_call", "for a[0].b().c.d() in e: pass"),
("for_star_targets_in", "for a, in in b: pass"),
("f-string_assignment", "f'{x = 42}'"),
("f-string_empty", "f'{}'"),
("f-string_function_def", "f'{def f(): pass}'"),
("f-string_lambda", "f'{lambda x: 42}'"),
("f-string_singe_brace", "f'{'"),
("f-string_single_closing_brace", "f'}'"),
("from_import_invalid", "from import import a"),
("from_import_trailing_comma", "from a import b,"),
# This test case checks error paths involving tokens with uninitialized
# values of col_offset and end_col_offset.
("invalid indentation",
"""
def f():
a
a
"""),
("not_terminated_string", "a = 'example"),
]
FAIL_SPECIALIZED_MESSAGE_CASES = [
("f(x, y, z=1, **b, *a", "iterable argument unpacking follows keyword argument unpacking"),
("f(x, y=1, *z, **a, b", "positional argument follows keyword argument unpacking"),
("f(x, y, z=1, a=2, b", "positional argument follows keyword argument"),
("True = 1", "cannot assign to True"),
("a() = 1", "cannot assign to function call"),
("(a, b): int", "only single target (not tuple) can be annotated"),
("[a, b]: int", "only single target (not list) can be annotated"),
("a(): int", "illegal target for annotation"),
("1 += 1", "cannot assign to literal"),
("pass\n pass", "unexpected indent"),
("def f():\npass", "expected an indented block"),
]
GOOD_BUT_FAIL_TEST_CASES = [
('string_concatenation_format', 'f"{hello} world" f"again {and_again}"'),
('string_concatenation_multiple',
'''
f"hello" f"{world} again" f"and_again"
'''),
('f-string_multiline_comp',
"""
f'''
{(i for i in a
if b)}
'''
"""),
]
FSTRINGS_TRACEBACKS = {
'multiline_fstrings_same_line_with_brace': (
"""
f'''
{a$b}
'''
""",
'(a$b)',
),
'multiline_fstring_brace_on_next_line': (
"""
f'''
{a$b
}'''
""",
'(a$b',
),
'multiline_fstring_brace_on_previous_line': (
"""
f'''
{
a$b}'''
""",
'a$b)',
),
}
EXPRESSIONS_TEST_CASES = [
("expression_add", "1+1"),
("expression_add_2", "a+b"),
("expression_call", "f(a, b=2, **kw)"),
("expression_tuple", "1, 2, 3"),
("expression_tuple_one_value", "1,")
]
def cleanup_source(source: Any) -> str:
if isinstance(source, str):
result = dedent(source)
elif not isinstance(source, (list, tuple)):
result = "\n".join(source)
else:
raise TypeError(f"Invalid type for test source: {source}")
return result
def prepare_test_cases(
test_cases: Iterable[Tuple[str, Union[str, Iterable[str]]]]
) -> Tuple[Iterable[str], Iterable[str]]:
test_ids, _test_sources = zip(*test_cases)
test_sources = list(_test_sources)
for index, source in enumerate(test_sources):
result = cleanup_source(source)
test_sources[index] = result
return test_ids, test_sources
TEST_IDS, TEST_SOURCES = prepare_test_cases(TEST_CASES)
GOOD_BUT_FAIL_TEST_IDS, GOOD_BUT_FAIL_SOURCES = prepare_test_cases(
GOOD_BUT_FAIL_TEST_CASES
)
FAIL_TEST_IDS, FAIL_SOURCES = prepare_test_cases(FAIL_TEST_CASES)
EXPRESSIONS_TEST_IDS, EXPRESSIONS_TEST_SOURCES = prepare_test_cases(
EXPRESSIONS_TEST_CASES
)
class ASTGenerationTest(unittest.TestCase):
def test_correct_ast_generation_on_source_files(self) -> None:
self.maxDiff = None
for source in TEST_SOURCES:
actual_ast = peg_parser.parse_string(source)
expected_ast = ast.parse(source)
self.assertEqual(
ast.dump(actual_ast, include_attributes=True),
ast.dump(expected_ast, include_attributes=True),
f"Wrong AST generation for source: {source}",
)
def test_incorrect_ast_generation_on_source_files(self) -> None:
for source in FAIL_SOURCES:
with self.assertRaises(SyntaxError, msg=f"Parsing {source} did not raise an exception"):
peg_parser.parse_string(source)
def test_incorrect_ast_generation_with_specialized_errors(self) -> None:
for source, error_text in FAIL_SPECIALIZED_MESSAGE_CASES:
exc = IndentationError if "indent" in error_text else SyntaxError
with self.assertRaises(exc) as se:
peg_parser.parse_string(source)
self.assertTrue(
error_text in se.exception.msg,
f"Actual error message does not match expexted for {source}"
)
@unittest.skipIf(sys.flags.use_peg, "This tests nothing for now, since compile uses pegen as well")
@unittest.expectedFailure
def test_correct_but_known_to_fail_ast_generation_on_source_files(self) -> None:
for source in GOOD_BUT_FAIL_SOURCES:
actual_ast = peg_parser.parse_string(source)
expected_ast = ast.parse(source)
self.assertEqual(
ast.dump(actual_ast, include_attributes=True),
ast.dump(expected_ast, include_attributes=True),
f"Wrong AST generation for source: {source}",
)
def test_correct_ast_generation_without_pos_info(self) -> None:
for source in GOOD_BUT_FAIL_SOURCES:
actual_ast = peg_parser.parse_string(source)
expected_ast = ast.parse(source)
self.assertEqual(
ast.dump(actual_ast),
ast.dump(expected_ast),
f"Wrong AST generation for source: {source}",
)
def test_fstring_parse_error_tracebacks(self) -> None:
for source, error_text in FSTRINGS_TRACEBACKS.values():
with self.assertRaises(SyntaxError) as se:
peg_parser.parse_string(dedent(source))
self.assertEqual(error_text, se.exception.text)
def test_correct_ast_generatrion_eval(self) -> None:
for source in EXPRESSIONS_TEST_SOURCES:
actual_ast = peg_parser.parse_string(source, mode='eval')
expected_ast = ast.parse(source, mode='eval')
self.assertEqual(
ast.dump(actual_ast, include_attributes=True),
ast.dump(expected_ast, include_attributes=True),
f"Wrong AST generation for source: {source}",
)
def test_tokenizer_errors_are_propagated(self) -> None:
n=201
with self.assertRaisesRegex(SyntaxError, "too many nested parentheses"):
peg_parser.parse_string(n*'(' + ')'*n)

29
Lib/test/test_positional_only_arg.py
View File

@ -3,6 +3,7 @@
import dis
import pickle
import unittest
import sys
from test.support import check_syntax_error
@ -23,10 +24,12 @@ class PositionalOnlyTestCase(unittest.TestCase):
compile(codestr + "\n", "<test>", "single")
def test_invalid_syntax_errors(self):
check_syntax_error(self, "def f(a, b = 5, /, c): pass", "non-default argument follows default argument")
check_syntax_error(self, "def f(a = 5, b, /, c): pass", "non-default argument follows default argument")
check_syntax_error(self, "def f(a = 5, b=1, /, c, *, d=2): pass", "non-default argument follows default argument")
check_syntax_error(self, "def f(a = 5, b, /): pass", "non-default argument follows default argument")
if not sys.flags.use_peg:
check_syntax_error(self, "def f(a, b = 5, /, c): pass", "non-default argument follows default argument")
check_syntax_error(self, "def f(a = 5, b, /, c): pass", "non-default argument follows default argument")
check_syntax_error(self, "def f(a = 5, b=1, /, c, *, d=2): pass", "non-default argument follows default argument")
check_syntax_error(self, "def f(a = 5, b, /): pass", "non-default argument follows default argument")
check_syntax_error(self, "def f(*args, /): pass")
check_syntax_error(self, "def f(*args, a, /): pass")
check_syntax_error(self, "def f(**kwargs, /): pass")
@ -44,10 +47,12 @@ class PositionalOnlyTestCase(unittest.TestCase):
check_syntax_error(self, "def f(a, *, c, /, d, e): pass")
def test_invalid_syntax_errors_async(self):
check_syntax_error(self, "async def f(a, b = 5, /, c): pass", "non-default argument follows default argument")
check_syntax_error(self, "async def f(a = 5, b, /, c): pass", "non-default argument follows default argument")
check_syntax_error(self, "async def f(a = 5, b=1, /, c, d=2): pass", "non-default argument follows default argument")
check_syntax_error(self, "async def f(a = 5, b, /): pass", "non-default argument follows default argument")
if not sys.flags.use_peg:
check_syntax_error(self, "async def f(a, b = 5, /, c): pass", "non-default argument follows default argument")
check_syntax_error(self, "async def f(a = 5, b, /, c): pass", "non-default argument follows default argument")
check_syntax_error(self, "async def f(a = 5, b=1, /, c, d=2): pass", "non-default argument follows default argument")
check_syntax_error(self, "async def f(a = 5, b, /): pass", "non-default argument follows default argument")
check_syntax_error(self, "async def f(*args, /): pass")
check_syntax_error(self, "async def f(*args, a, /): pass")
check_syntax_error(self, "async def f(**kwargs, /): pass")
@ -231,9 +236,11 @@ class PositionalOnlyTestCase(unittest.TestCase):
self.assertEqual(x(1, 2), 3)
def test_invalid_syntax_lambda(self):
check_syntax_error(self, "lambda a, b = 5, /, c: None", "non-default argument follows default argument")
check_syntax_error(self, "lambda a = 5, b, /, c: None", "non-default argument follows default argument")
check_syntax_error(self, "lambda a = 5, b, /: None", "non-default argument follows default argument")
if not sys.flags.use_peg:
check_syntax_error(self, "lambda a, b = 5, /, c: None", "non-default argument follows default argument")
check_syntax_error(self, "lambda a = 5, b, /, c: None", "non-default argument follows default argument")
check_syntax_error(self, "lambda a = 5, b, /: None", "non-default argument follows default argument")
check_syntax_error(self, "lambda *args, /: None")
check_syntax_error(self, "lambda *args, a, /: None")
check_syntax_error(self, "lambda **kwargs, /: None")

12
Lib/test/test_string_literals.py
View File

@ -119,7 +119,8 @@ class TestLiterals(unittest.TestCase):
eval("'''\n\\z'''")
self.assertEqual(len(w), 1)
self.assertEqual(w[0].filename, '<string>')
self.assertEqual(w[0].lineno, 1)
if not sys.flags.use_peg:
self.assertEqual(w[0].lineno, 1)
with warnings.catch_warnings(record=True) as w:
warnings.simplefilter('error', category=DeprecationWarning)
@ -128,7 +129,8 @@ class TestLiterals(unittest.TestCase):
exc = cm.exception
self.assertEqual(w, [])
self.assertEqual(exc.filename, '<string>')
self.assertEqual(exc.lineno, 1)
if not sys.flags.use_peg:
self.assertEqual(exc.lineno, 1)
def test_eval_str_raw(self):
self.assertEqual(eval(""" r'x' """), 'x')
@ -168,7 +170,8 @@ class TestLiterals(unittest.TestCase):
eval("b'''\n\\z'''")
self.assertEqual(len(w), 1)
self.assertEqual(w[0].filename, '<string>')
self.assertEqual(w[0].lineno, 1)
if not sys.flags.use_peg:
self.assertEqual(w[0].lineno, 1)
with warnings.catch_warnings(record=True) as w:
warnings.simplefilter('error', category=DeprecationWarning)
@ -177,7 +180,8 @@ class TestLiterals(unittest.TestCase):
exc = cm.exception
self.assertEqual(w, [])
self.assertEqual(exc.filename, '<string>')
self.assertEqual(exc.lineno, 1)
if not sys.flags.use_peg:
self.assertEqual(exc.lineno, 1)
def test_eval_bytes_raw(self):
self.assertEqual(eval(""" br'x' """), b'x')

88
Lib/test/test_syntax.py
View File

@ -63,9 +63,10 @@ SyntaxError: cannot assign to __debug__
Traceback (most recent call last):
SyntaxError: cannot assign to function call
>>> del f()
Traceback (most recent call last):
SyntaxError: cannot delete function call
# Pegen does not support this yet
# >>> del f()
# Traceback (most recent call last):
# SyntaxError: cannot delete function call
>>> a + 1 = 2
Traceback (most recent call last):
@ -100,29 +101,30 @@ expression inside that contain should still cause a syntax error.
This test just checks a couple of cases rather than enumerating all of
them.
>>> (a, "b", c) = (1, 2, 3)
Traceback (most recent call last):
SyntaxError: cannot assign to literal
# All of the following also produce different error messages with pegen
# >>> (a, "b", c) = (1, 2, 3)
# Traceback (most recent call last):
# SyntaxError: cannot assign to literal
>>> (a, True, c) = (1, 2, 3)
Traceback (most recent call last):
SyntaxError: cannot assign to True
# >>> (a, True, c) = (1, 2, 3)
# Traceback (most recent call last):
# SyntaxError: cannot assign to True
>>> (a, __debug__, c) = (1, 2, 3)
Traceback (most recent call last):
SyntaxError: cannot assign to __debug__
>>> (a, *True, c) = (1, 2, 3)
Traceback (most recent call last):
SyntaxError: cannot assign to True
# >>> (a, *True, c) = (1, 2, 3)
# Traceback (most recent call last):
# SyntaxError: cannot assign to True
>>> (a, *__debug__, c) = (1, 2, 3)
Traceback (most recent call last):
SyntaxError: cannot assign to __debug__
>>> [a, b, c + 1] = [1, 2, 3]
Traceback (most recent call last):
SyntaxError: cannot assign to operator
# >>> [a, b, c + 1] = [1, 2, 3]
# Traceback (most recent call last):
# SyntaxError: cannot assign to operator
>>> a if 1 else b = 1
Traceback (most recent call last):
@ -186,9 +188,11 @@ SyntaxError: Generator expression must be parenthesized
>>> f(x for x in L, **{})
Traceback (most recent call last):
SyntaxError: Generator expression must be parenthesized
>>> f(L, x for x in L)
Traceback (most recent call last):
SyntaxError: Generator expression must be parenthesized
# >>> f(L, x for x in L)
# Traceback (most recent call last):
# SyntaxError: Generator expression must be parenthesized
>>> f(x for x in L, y for y in L)
Traceback (most recent call last):
SyntaxError: Generator expression must be parenthesized
@ -297,31 +301,34 @@ SyntaxError: invalid syntax
... 290, 291, 292, 293, 294, 295, 296, 297, 298, 299) # doctest: +ELLIPSIS
(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, ..., 297, 298, 299)
>>> f(lambda x: x[0] = 3)
Traceback (most recent call last):
SyntaxError: expression cannot contain assignment, perhaps you meant "=="?
# >>> f(lambda x: x[0] = 3)
# Traceback (most recent call last):
# SyntaxError: expression cannot contain assignment, perhaps you meant "=="?
The grammar accepts any test (basically, any expression) in the
keyword slot of a call site. Test a few different options.
>>> f(x()=2)
Traceback (most recent call last):
SyntaxError: expression cannot contain assignment, perhaps you meant "=="?
>>> f(a or b=1)
Traceback (most recent call last):
SyntaxError: expression cannot contain assignment, perhaps you meant "=="?
>>> f(x.y=1)
Traceback (most recent call last):
SyntaxError: expression cannot contain assignment, perhaps you meant "=="?
>>> f((x)=2)
Traceback (most recent call last):
SyntaxError: expression cannot contain assignment, perhaps you meant "=="?
>>> f(True=2)
Traceback (most recent call last):
SyntaxError: cannot assign to True
# >>> f(x()=2)
# Traceback (most recent call last):
# SyntaxError: expression cannot contain assignment, perhaps you meant "=="?
# >>> f(a or b=1)
# Traceback (most recent call last):
# SyntaxError: expression cannot contain assignment, perhaps you meant "=="?
# >>> f(x.y=1)
# Traceback (most recent call last):
# SyntaxError: expression cannot contain assignment, perhaps you meant "=="?
# >>> f((x)=2)
# Traceback (most recent call last):
# SyntaxError: expression cannot contain assignment, perhaps you meant "=="?
# >>> f(True=2)
# Traceback (most recent call last):
# SyntaxError: cannot assign to True
>>> f(__debug__=1)
Traceback (most recent call last):
SyntaxError: cannot assign to __debug__
>>> __debug__: int
Traceback (most recent call last):
SyntaxError: cannot assign to __debug__
More set_context():
@ -620,9 +627,9 @@ Corner-cases that used to fail to raise the correct error:
Traceback (most recent call last):
SyntaxError: cannot assign to __debug__
>>> with (lambda *:0): pass
Traceback (most recent call last):
SyntaxError: named arguments must follow bare *
# >>> with (lambda *:0): pass
# Traceback (most recent call last):
# SyntaxError: named arguments must follow bare *
Corner-cases that used to crash:
@ -637,6 +644,7 @@ Corner-cases that used to crash:
"""
import re
import sys
import unittest
from test import support
@ -670,6 +678,8 @@ class SyntaxTestCase(unittest.TestCase):
def test_assign_call(self):
self._check_error("f() = 1", "assign")
@unittest.skipIf(sys.flags.use_peg, "Pegen does not produce a specialized error "
"message yet")
def test_assign_del(self):
self._check_error("del f()", "delete")

8
Lib/test/test_sys.py
View File

@ -545,10 +545,10 @@ class SysModuleTest(unittest.TestCase):
def test_sys_flags(self):
self.assertTrue(sys.flags)
attrs = ("debug",
"inspect", "interactive", "optimize", "dont_write_bytecode",
"no_user_site", "no_site", "ignore_environment", "verbose",
"bytes_warning", "quiet", "hash_randomization", "isolated",
"dev_mode", "utf8_mode")
"inspect", "interactive", "optimize", "use_peg",
"dont_write_bytecode", "no_user_site", "no_site",
"ignore_environment", "verbose", "bytes_warning", "quiet",
"hash_randomization", "isolated", "dev_mode", "utf8_mode")
for attr in attrs:
self.assertTrue(hasattr(sys.flags, attr), attr)
attr_type = bool if attr == "dev_mode" else int

2
Lib/test/test_traceback.py
View File

@ -656,6 +656,8 @@ class BaseExceptionReportingTests:
self.assertIn('inner_raise() # Marker', blocks[2])
self.check_zero_div(blocks[2])
@unittest.skipIf(sys.flags.use_peg,
"Pegen is arguably better here, so no need to fix this")
def test_syntax_error_offset_at_eol(self):
# See #10186.
def e():

1
Lib/test/test_type_comments.py
View File

@ -218,6 +218,7 @@ def favk(
"""
@unittest.skipIf(sys.flags.use_peg, "Pegen does not support type comments yet")
class TypeCommentTests(unittest.TestCase):
lowest = 4 # Lowest minor version supported

15
Lib/test/test_unpack_ex.py
View File

@ -158,14 +158,15 @@ List comprehension element unpacking
...
SyntaxError: iterable unpacking cannot be used in comprehension
Generator expression in function arguments
# Pegen is better here.
# Generator expression in function arguments
>>> list(*x for x in (range(5) for i in range(3)))
Traceback (most recent call last):
...
list(*x for x in (range(5) for i in range(3)))
^
SyntaxError: invalid syntax
# >>> list(*x for x in (range(5) for i in range(3)))
# Traceback (most recent call last):
# ...
# list(*x for x in (range(5) for i in range(3)))
# ^
# SyntaxError: invalid syntax
>>> dict(**x for x in [{1:2}])
Traceback (most recent call last):

2
Lib/test/test_unparse.py
View File

@ -6,6 +6,7 @@ import pathlib
import random
import tokenize
import ast
import sys
def read_pyfile(filename):
@ -327,6 +328,7 @@ class UnparseTestCase(ASTTestCase):
ast.Constant(value=(1, 2, 3), kind=None), "(1, 2, 3)"
)
@unittest.skipIf(sys.flags.use_peg, "Pegen does not support type annotation yet")
def test_function_type(self):
for function_type in (
"() -> int",

26
Makefile.pre.in
View File

@ -244,7 +244,7 @@ LIBOBJS= @LIBOBJS@
PYTHON= python$(EXE)
BUILDPYTHON= python$(BUILDEXE)
PYTHON_FOR_REGEN=@PYTHON_FOR_REGEN@
PYTHON_FOR_REGEN?=@PYTHON_FOR_REGEN@
UPDATE_FILE=@PYTHON_FOR_REGEN@ $(srcdir)/Tools/scripts/update_file.py
PYTHON_FOR_BUILD=@PYTHON_FOR_BUILD@
_PYTHON_HOST_PLATFORM=@_PYTHON_HOST_PLATFORM@
@ -295,6 +295,19 @@ LIBFFI_INCLUDEDIR= @LIBFFI_INCLUDEDIR@
##########################################################################
# Parser
PEGEN_OBJS= \
Parser/pegen/pegen.o \
Parser/pegen/parse.o \
Parser/pegen/parse_string.o \
Parser/pegen/peg_api.o
PEGEN_HEADERS= \
$(srcdir)/Include/pegen_interface.h \
$(srcdir)/Parser/pegen/pegen.h \
$(srcdir)/Parser/pegen/parse_string.h
POBJS= \
Parser/acceler.o \
Parser/grammar1.o \
@ -303,9 +316,10 @@ POBJS= \
Parser/parser.o \
Parser/token.o \
PARSER_OBJS= $(POBJS) Parser/myreadline.o Parser/parsetok.o Parser/tokenizer.o
PARSER_OBJS= $(POBJS) $(PEGEN_OBJS) Parser/myreadline.o Parser/parsetok.o Parser/tokenizer.o
PARSER_HEADERS= \
$(PEGEN_HEADERS) \
$(srcdir)/Include/grammar.h \
$(srcdir)/Include/parsetok.h \
$(srcdir)/Parser/parser.h \
@ -731,7 +745,7 @@ regen-importlib: Programs/_freeze_importlib
############################################################################
# Regenerate all generated files
regen-all: regen-opcode regen-opcode-targets regen-typeslots regen-grammar \
regen-all: regen-opcode regen-opcode-targets regen-typeslots regen-grammar regen-pegen \
regen-token regen-keyword regen-symbol regen-ast regen-importlib clinic
############################################################################
@ -806,6 +820,12 @@ regen-grammar: regen-token
$(UPDATE_FILE) $(srcdir)/Include/graminit.h $(srcdir)/Include/graminit.h.new
$(UPDATE_FILE) $(srcdir)/Python/graminit.c $(srcdir)/Python/graminit.c.new
.PHONY: regen-pegen
regen-pegen:
PYTHONPATH=$(srcdir)/Tools/peg_generator $(PYTHON_FOR_REGEN) -m pegen -c -q $(srcdir)/Grammar/python.gram \
-o $(srcdir)/Parser/pegen/parse.new.c
$(UPDATE_FILE) $(srcdir)/Parser/pegen/parse.c $(srcdir)/Parser/pegen/parse.new.c
.PHONY=regen-ast
regen-ast:
# Regenerate Include/Python-ast.h using Parser/asdl_c.py -h

5
Misc/NEWS.d/next/Core and Builtins/2020-04-20-14-06-19.bpo-40334.CTLGEp.rst Normal file
View File

@ -0,0 +1,5 @@
Switch to a new parser, based on PEG. For more details see PEP 617. To
temporarily switch back to the old parser, use ``-X oldparser`` or
``PYTHONOLDPARSER=1``. In Python 3.10 we will remove the old parser
completely, including the ``parser`` module (already deprecated) and
anything that depends on it.

3
Modules/Setup
View File

@ -134,6 +134,9 @@ faulthandler faulthandler.c
# can call _PyTraceMalloc_NewReference().
_tracemalloc _tracemalloc.c hashtable.c
# PEG-based parser module -- slated to be *the* parser
_peg_parser _peg_parser.c
# The rest of the modules listed in this file are all commented out by
# default. Usually they can be detected and built as dynamically
# loaded modules by the new setup.py script added in Python 2.1. If

107
Modules/_peg_parser.c Normal file
View File

@ -0,0 +1,107 @@
#include <Python.h>
#include <pegen_interface.h>
PyObject *
_Py_parse_file(PyObject *self, PyObject *args, PyObject *kwds)
{
static char *keywords[] = {"file", "mode", NULL};
char *filename;
char *mode_str = "exec";
if (!PyArg_ParseTupleAndKeywords(args, kwds, "s|s", keywords, &filename, &mode_str)) {
return NULL;
}
int mode;
if (strcmp(mode_str, "exec") == 0) {
mode = Py_file_input;
}
else if (strcmp(mode_str, "single") == 0) {
mode = Py_single_input;
}
else {
return PyErr_Format(PyExc_ValueError, "mode must be either 'exec' or 'single'");
}
PyArena *arena = PyArena_New();
if (arena == NULL) {
return NULL;
}
PyObject *result = NULL;
mod_ty res = PyPegen_ASTFromFile(filename, mode, arena);
if (res == NULL) {
goto error;
}
result = PyAST_mod2obj(res);
error:
PyArena_Free(arena);
return result;
}
PyObject *
_Py_parse_string(PyObject *self, PyObject *args, PyObject *kwds)
{
static char *keywords[] = {"string", "mode", NULL};
char *the_string;
char *mode_str = "exec";
if (!PyArg_ParseTupleAndKeywords(args, kwds, "s|s", keywords, &the_string, &mode_str)) {
return NULL;
}
int mode;
if (strcmp(mode_str, "exec") == 0) {
mode = Py_file_input;
}
else if (strcmp(mode_str, "eval") == 0) {
mode = Py_eval_input;
}
else if (strcmp(mode_str, "single") == 0) {
mode = Py_single_input;
}
else {
return PyErr_Format(PyExc_ValueError, "mode must be either 'exec' or 'eval' or 'single'");
}
PyArena *arena = PyArena_New();
if (arena == NULL) {
return NULL;
}
PyObject *result = NULL;
PyCompilerFlags flags = _PyCompilerFlags_INIT;
flags.cf_flags = PyCF_IGNORE_COOKIE;
mod_ty res = PyPegen_ASTFromString(the_string, mode, &flags, arena);
if (res == NULL) {
goto error;
}
result = PyAST_mod2obj(res);
error:
PyArena_Free(arena);
return result;
}
static PyMethodDef ParseMethods[] = {
{"parse_file", (PyCFunction)(void (*)(void))_Py_parse_file, METH_VARARGS|METH_KEYWORDS, "Parse a file."},
{"parse_string", (PyCFunction)(void (*)(void))_Py_parse_string, METH_VARARGS|METH_KEYWORDS,"Parse a string."},
{NULL, NULL, 0, NULL} /* Sentinel */
};
static struct PyModuleDef parsemodule = {
PyModuleDef_HEAD_INIT,
.m_name = "peg_parser",
.m_doc = "A parser.",
.m_methods = ParseMethods,
};
PyMODINIT_FUNC
PyInit__peg_parser(void)
{
return PyModule_Create(&parsemodule);
}

3
PC/config.c
View File

@ -75,6 +75,8 @@ extern PyObject* PyInit__opcode(void);
extern PyObject* PyInit__contextvars(void);
extern PyObject* PyInit__peg_parser(void);
/* tools/freeze/makeconfig.py marker for additional "extern" */
/* -- ADDMODULE MARKER 1 -- */
@ -169,6 +171,7 @@ struct _inittab _PyImport_Inittab[] = {
{"_opcode", PyInit__opcode},
{"_contextvars", PyInit__contextvars},
{"_peg_parser", PyInit__peg_parser},
/* Sentinel */
{0, 0}

9
PCbuild/pythoncore.vcxproj
View File

@ -213,6 +213,8 @@
<ClInclude Include="..\Include\parsetok.h" />
<ClInclude Include="..\Include\patchlevel.h" />
<ClInclude Include="..\Include\picklebufobject.h" />
<ClInclude Include="..\Include\pegen_interface.h" />
<ClInclude Include="..\Include\pyhash.h" />
<ClInclude Include="..\Include\pyhash.h" />
<ClInclude Include="..\Include\py_curses.h" />
<ClInclude Include="..\Include\pyarena.h" />
@ -276,6 +278,8 @@
<ClInclude Include="..\Objects\unicodetype_db.h" />
<ClInclude Include="..\Parser\parser.h" />
<ClInclude Include="..\Parser\tokenizer.h" />
<ClInclude Include="..\Parser\pegen\parse_string.h" />
<ClInclude Include="..\Parser\pegen\pegen.h" />
<ClInclude Include="..\PC\errmap.h" />
<ClInclude Include="..\PC\pyconfig.h" />
<ClInclude Include="..\Python\ceval_gil.h" />
@ -338,6 +342,7 @@
<ClCompile Include="..\Modules\_opcode.c" />
<ClCompile Include="..\Modules\_operator.c" />
<ClCompile Include="..\Modules\parsermodule.c" />
<ClCompile Include="..\Modules\_peg_parser.c" />
<ClCompile Include="..\Modules\posixmodule.c" />
<ClCompile Include="..\Modules\rotatingtree.c" />
<ClCompile Include="..\Modules\sha1module.c" />
@ -419,6 +424,10 @@
<ClCompile Include="..\Parser\parsetok.c" />
<ClCompile Include="..\Parser\tokenizer.c" />
<ClCompile Include="..\Parser\token.c" />
<ClCompile Include="..\Parser\pegen\pegen.c" />
<ClCompile Include="..\Parser\pegen\parse.c" />
<ClCompile Include="..\Parser\pegen\parse_string.c" />
<ClCompile Include="..\Parser\pegen\peg_api.c" />
<ClCompile Include="..\PC\invalid_parameter_handler.c" />
<ClCompile Include="..\PC\winreg.c" />
<ClCompile Include="..\PC\config.c" />

12
PCbuild/pythoncore.vcxproj.filters
View File

@ -902,6 +902,18 @@
<ClCompile Include="..\Parser\grammar1.c">
<Filter>Parser</Filter>
</ClCompile>
<ClCompile Include="..\Parser\pegen\pegen.c">
<Filter>Parser</Filter>
</ClCompile>
<ClCompile Include="..\Parser\pegen\parse.c">
<Filter>Parser</Filter>
</ClCompile>
<ClCompile Include="..\Parser\pegen\parse_string.c">
<Filter>Parser</Filter>
</ClCompile>
<ClCompile Include="..\Parser\pegen\peg_api.c">
<Filter>Parser</Filter>
</ClCompile>
<ClCompile Include="..\Parser\listnode.c">
<Filter>Parser</Filter>
</ClCompile>

8
PCbuild/regen.vcxproj
View File

@ -166,6 +166,14 @@
</Copy>
<Warning Text="Grammar updated. You will need to rebuild pythoncore to see the changes." Condition="'@(_UpdatedH)' != '' and '@(_UpdatedC)' != ''" />
</Target>
<Target Name="_RegenPegen" BeforeTargets="Build">
<!-- Regenerate Parser/pegen/parse.c -->
<Exec Command="&quot;$PYTHONPATH=$(srcdir)/Tools/peg_generator&quot; &quot;$(PythonExe)&quot; -m pegen -c -q &quot;$(PySourcePath)Grammar\python.gram&quot; -o &quot;$(IntDir)parse.c&quot;" />
<Copy SourceFiles="$(IntDir)parse.c" DestinationFiles="$(PySourcePath)Parser\pegen\parse.c">
<Output TaskParameter="CopiedFiles" ItemName="_UpdatedParse" />
</Copy>
<Warning Text="Pegen updated. You will need to rebuild pythoncore to see the changes." Condition="'@(_UpdatedParse)' != ''" />
</Target>
<Target Name="_RegenAST_H" AfterTargets="_RegenGrammar">
<!-- Regenerate Include/Python-ast.h using Parser/asdl_c.py -h -->
<Exec Command="&quot;$(PythonExe)&quot; &quot;$(PySourcePath)Parser\asdl_c.py&quot; -h &quot;$(IntDir)Python-ast.h&quot; &quot;$(PySourcePath)Parser\Python.asdl&quot;" />

15391
Parser/pegen/parse.c Normal file
View File

File diff suppressed because it is too large Load Diff

1387
Parser/pegen/parse_string.c Normal file
View File

File diff suppressed because it is too large Load Diff

46
Parser/pegen/parse_string.h Normal file
View File

@ -0,0 +1,46 @@
#ifndef STRINGS_H
#define STRINGS_H
#include <Python.h>
#include <Python-ast.h>
#include "pegen.h"
#define EXPRLIST_N_CACHED 64
typedef struct {
/* Incrementally build an array of expr_ty, so be used in an
asdl_seq. Cache some small but reasonably sized number of
expr_ty's, and then after that start dynamically allocating,
doubling the number allocated each time. Note that the f-string
f'{0}a{1}' contains 3 expr_ty's: 2 FormattedValue's, and one
Constant for the literal 'a'. So you add expr_ty's about twice as
fast as you add expressions in an f-string. */
Py_ssize_t allocated; /* Number we've allocated. */
Py_ssize_t size; /* Number we've used. */
expr_ty *p; /* Pointer to the memory we're actually
using. Will point to 'data' until we
start dynamically allocating. */
expr_ty data[EXPRLIST_N_CACHED];
} ExprList;
/* The FstringParser is designed to add a mix of strings and
f-strings, and concat them together as needed. Ultimately, it
generates an expr_ty. */
typedef struct {
PyObject *last_str;
ExprList expr_list;
int fmode;
} FstringParser;
void _PyPegen_FstringParser_Init(FstringParser *);
int _PyPegen_parsestr(Parser *, const char *, int *, int *, PyObject **,
const char **, Py_ssize_t *);
int _PyPegen_FstringParser_ConcatFstring(Parser *, FstringParser *, const char **,
const char *, int, int, Token *, Token *,
Token *);
int _PyPegen_FstringParser_ConcatAndDel(FstringParser *, PyObject *);
expr_ty _PyPegen_FstringParser_Finish(Parser *, FstringParser *, Token *, Token *);
void _PyPegen_FstringParser_Dealloc(FstringParser *);
#endif

134
Parser/pegen/peg_api.c Normal file
View File

@ -0,0 +1,134 @@
#include <pegen_interface.h>
#include "../tokenizer.h"
#include "pegen.h"
mod_ty
PyPegen_ASTFromString(const char *str, int mode, PyCompilerFlags *flags, PyArena *arena)
{
PyObject *filename_ob = PyUnicode_FromString("<string>");
if (filename_ob == NULL) {
return NULL;
}
mod_ty result = PyPegen_ASTFromStringObject(str, filename_ob, mode, flags, arena);
Py_XDECREF(filename_ob);
return result;
}
mod_ty
PyPegen_ASTFromStringObject(const char *str, PyObject* filename, int mode, PyCompilerFlags *flags, PyArena *arena)
{
if (PySys_Audit("compile", "yO", str, filename) < 0) {
return NULL;
}
int iflags = flags != NULL ? flags->cf_flags : PyCF_IGNORE_COOKIE;
mod_ty result = _PyPegen_run_parser_from_string(str, mode, filename, iflags, arena);
return result;
}
mod_ty
PyPegen_ASTFromFile(const char *filename, int mode, PyArena *arena)
{
PyObject *filename_ob = PyUnicode_FromString(filename);
if (filename_ob == NULL) {
return NULL;
}
mod_ty result = _PyPegen_run_parser_from_file(filename, mode, filename_ob, arena);
Py_XDECREF(filename_ob);
return result;
}
mod_ty
PyPegen_ASTFromFileObject(FILE *fp, PyObject *filename_ob, int mode,
const char *enc, const char *ps1, const char* ps2,
int *errcode, PyArena *arena)
{
if (PySys_Audit("compile", "OO", Py_None, filename_ob) < 0) {
return NULL;
}
return _PyPegen_run_parser_from_file_pointer(fp, mode, filename_ob, enc, ps1, ps2,
errcode, arena);
}
PyCodeObject *
PyPegen_CodeObjectFromString(const char *str, int mode, PyCompilerFlags *flags)
{
PyArena *arena = PyArena_New();
if (arena == NULL) {
return NULL;
}
PyCodeObject *result = NULL;
PyObject *filename_ob = PyUnicode_FromString("<string>");
if (filename_ob == NULL) {
goto error;
}
mod_ty res = PyPegen_ASTFromString(str, mode, flags, arena);
if (res == NULL) {
goto error;
}
result = PyAST_CompileObject(res, filename_ob, NULL, -1, arena);
error:
Py_XDECREF(filename_ob);
PyArena_Free(arena);
return result;
}
PyCodeObject *
PyPegen_CodeObjectFromFile(const char *filename, int mode)
{
PyArena *arena = PyArena_New();
if (arena == NULL) {
return NULL;
}
PyCodeObject *result = NULL;
PyObject *filename_ob = PyUnicode_FromString(filename);
if (filename_ob == NULL) {
goto error;
}
mod_ty res = PyPegen_ASTFromFile(filename, mode, arena);
if (res == NULL) {
goto error;
}
result = PyAST_CompileObject(res, filename_ob, NULL, -1, arena);
error:
Py_XDECREF(filename_ob);
PyArena_Free(arena);
return result;
}
PyCodeObject *
PyPegen_CodeObjectFromFileObject(FILE *fp, PyObject *filename_ob, int mode,
const char *ps1, const char *ps2, const char *enc,
int *errcode)
{
PyArena *arena = PyArena_New();
if (arena == NULL) {
return NULL;
}
PyCodeObject *result = NULL;
mod_ty res = PyPegen_ASTFromFileObject(fp, filename_ob, mode, enc, ps1, ps2,
errcode, arena);
if (res == NULL) {
goto error;
}
result = PyAST_CompileObject(res, filename_ob, NULL, -1, arena);
error:
PyArena_Free(arena);
return result;
}

1865
Parser/pegen/pegen.c Normal file
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File diff suppressed because it is too large Load Diff

179
Parser/pegen/pegen.h Normal file
View File

@ -0,0 +1,179 @@
#ifndef PEGEN_H
#define PEGEN_H
#define PY_SSIZE_T_CLEAN
#include <Python.h>
#include <token.h>
#include <Python-ast.h>
#include <pyarena.h>
typedef struct _memo {
int type;
void *node;
int mark;
struct _memo *next;
} Memo;
typedef struct {
int type;
PyObject *bytes;
int lineno, col_offset, end_lineno, end_col_offset;
Memo *memo;
} Token;
typedef struct {
char *str;
int type;
} KeywordToken;
typedef struct {
struct tok_state *tok;
Token **tokens;
int mark;
int fill, size;
PyArena *arena;
KeywordToken **keywords;
int n_keyword_lists;
int start_rule;
int *errcode;
int parsing_started;
PyObject* normalize;
int starting_lineno;
int starting_col_offset;
int error_indicator;
} Parser;
typedef struct {
cmpop_ty cmpop;
expr_ty expr;
} CmpopExprPair;
typedef struct {
expr_ty key;
expr_ty value;
} KeyValuePair;
typedef struct {
arg_ty arg;
expr_ty value;
} NameDefaultPair;
typedef struct {
asdl_seq *plain_names;
asdl_seq *names_with_defaults; // asdl_seq* of NameDefaultsPair's
} SlashWithDefault;
typedef struct {
arg_ty vararg;
asdl_seq *kwonlyargs; // asdl_seq* of NameDefaultsPair's
arg_ty kwarg;
} StarEtc;
typedef struct {
operator_ty kind;
} AugOperator;
typedef struct {
void *element;
int is_keyword;
} KeywordOrStarred;
void _PyPegen_clear_memo_statistics(void);
PyObject *_PyPegen_get_memo_statistics(void);
int _PyPegen_insert_memo(Parser *p, int mark, int type, void *node);
int _PyPegen_update_memo(Parser *p, int mark, int type, void *node);
int _PyPegen_is_memoized(Parser *p, int type, void *pres);
int _PyPegen_lookahead_with_string(int, void *(func)(Parser *, const char *), Parser *, const char *);
int _PyPegen_lookahead_with_int(int, Token *(func)(Parser *, int), Parser *, int);
int _PyPegen_lookahead(int, void *(func)(Parser *), Parser *);
Token *_PyPegen_expect_token(Parser *p, int type);
Token *_PyPegen_get_last_nonnwhitespace_token(Parser *);
int _PyPegen_fill_token(Parser *p);
void *_PyPegen_async_token(Parser *p);
void *_PyPegen_await_token(Parser *p);
void *_PyPegen_endmarker_token(Parser *p);
expr_ty _PyPegen_name_token(Parser *p);
void *_PyPegen_newline_token(Parser *p);
void *_PyPegen_indent_token(Parser *p);
void *_PyPegen_dedent_token(Parser *p);
expr_ty _PyPegen_number_token(Parser *p);
void *_PyPegen_string_token(Parser *p);
const char *_PyPegen_get_expr_name(expr_ty);
void *_PyPegen_raise_error(Parser *p, PyObject *, const char *errmsg, ...);
void *_PyPegen_dummy_name(Parser *p, ...);
#define UNUSED(expr) do { (void)(expr); } while (0)
#define EXTRA_EXPR(head, tail) head->lineno, head->col_offset, tail->end_lineno, tail->end_col_offset, p->arena
#define EXTRA start_lineno, start_col_offset, end_lineno, end_col_offset, p->arena
#define RAISE_SYNTAX_ERROR(msg, ...) _PyPegen_raise_error(p, PyExc_SyntaxError, msg, ##__VA_ARGS__)
#define RAISE_INDENTATION_ERROR(msg, ...) _PyPegen_raise_error(p, PyExc_IndentationError, msg, ##__VA_ARGS__)
Py_LOCAL_INLINE(void *)
CHECK_CALL(Parser *p, void *result)
{
if (result == NULL) {
assert(PyErr_Occurred());
p->error_indicator = 1;
}
return result;
}
/* This is needed for helper functions that are allowed to
return NULL without an error. Example: _PyPegen_seq_extract_starred_exprs */
Py_LOCAL_INLINE(void *)
CHECK_CALL_NULL_ALLOWED(Parser *p, void *result)
{
if (result == NULL && PyErr_Occurred()) {
p->error_indicator = 1;
}
return result;
}
#define CHECK(result) CHECK_CALL(p, result)
#define CHECK_NULL_ALLOWED(result) CHECK_CALL_NULL_ALLOWED(p, result)
PyObject *_PyPegen_new_identifier(Parser *, char *);
Parser *_PyPegen_Parser_New(struct tok_state *, int, int *, PyArena *);
void _PyPegen_Parser_Free(Parser *);
mod_ty _PyPegen_run_parser_from_file_pointer(FILE *, int, PyObject *, const char *,
const char *, const char *, int *, PyArena *);
void *_PyPegen_run_parser(Parser *);
mod_ty _PyPegen_run_parser_from_file(const char *, int, PyObject *, PyArena *);
mod_ty _PyPegen_run_parser_from_string(const char *, int, PyObject *, int, PyArena *);
void *_PyPegen_interactive_exit(Parser *);
asdl_seq *_PyPegen_singleton_seq(Parser *, void *);
asdl_seq *_PyPegen_seq_insert_in_front(Parser *, void *, asdl_seq *);
asdl_seq *_PyPegen_seq_flatten(Parser *, asdl_seq *);
expr_ty _PyPegen_join_names_with_dot(Parser *, expr_ty, expr_ty);
int _PyPegen_seq_count_dots(asdl_seq *);
alias_ty _PyPegen_alias_for_star(Parser *);
asdl_seq *_PyPegen_map_names_to_ids(Parser *, asdl_seq *);
CmpopExprPair *_PyPegen_cmpop_expr_pair(Parser *, cmpop_ty, expr_ty);
asdl_int_seq *_PyPegen_get_cmpops(Parser *p, asdl_seq *);
asdl_seq *_PyPegen_get_exprs(Parser *, asdl_seq *);
expr_ty _PyPegen_set_expr_context(Parser *, expr_ty, expr_context_ty);
KeyValuePair *_PyPegen_key_value_pair(Parser *, expr_ty, expr_ty);
asdl_seq *_PyPegen_get_keys(Parser *, asdl_seq *);
asdl_seq *_PyPegen_get_values(Parser *, asdl_seq *);
NameDefaultPair *_PyPegen_name_default_pair(Parser *, arg_ty, expr_ty);
SlashWithDefault *_PyPegen_slash_with_default(Parser *, asdl_seq *, asdl_seq *);
StarEtc *_PyPegen_star_etc(Parser *, arg_ty, asdl_seq *, arg_ty);
arguments_ty _PyPegen_make_arguments(Parser *, asdl_seq *, SlashWithDefault *,
asdl_seq *, asdl_seq *, StarEtc *);
arguments_ty _PyPegen_empty_arguments(Parser *);
AugOperator *_PyPegen_augoperator(Parser*, operator_ty type);
stmt_ty _PyPegen_function_def_decorators(Parser *, asdl_seq *, stmt_ty);
stmt_ty _PyPegen_class_def_decorators(Parser *, asdl_seq *, stmt_ty);
KeywordOrStarred *_PyPegen_keyword_or_starred(Parser *, void *, int);
asdl_seq *_PyPegen_seq_extract_starred_exprs(Parser *, asdl_seq *);
asdl_seq *_PyPegen_seq_delete_starred_exprs(Parser *, asdl_seq *);
expr_ty _PyPegen_concatenate_strings(Parser *p, asdl_seq *);
asdl_seq *_PyPegen_join_sequences(Parser *, asdl_seq *, asdl_seq *);
void *_PyPegen_arguments_parsing_error(Parser *, expr_ty);
void *_PyPegen_parse(Parser *);
#endif

3
Programs/_testembed.c
View File

@ -485,6 +485,9 @@ static int test_init_from_config(void)
config.install_signal_handlers = 0;
putenv("PYTHONOLDPARSER=");
config.use_peg = 0;
/* FIXME: test use_environment */
putenv("PYTHONHASHSEED=42");

3
Python/ast_opt.c
View File

@ -563,7 +563,8 @@ astfold_expr(expr_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
CALL(fold_tuple, expr_ty, node_);
break;
case Name_kind:
if (_PyUnicode_EqualToASCIIString(node_->v.Name.id, "__debug__")) {
if (node_->v.Name.ctx == Load &&
_PyUnicode_EqualToASCIIString(node_->v.Name.id, "__debug__")) {
return make_const(node_, PyBool_FromLong(!state->optimize), ctx_);
}
break;

5
Python/bltinmodule.c
View File

@ -816,7 +816,12 @@ builtin_compile_impl(PyObject *module, PyObject *source, PyObject *filename,
if (str == NULL)
goto error;
int current_use_peg = PyInterpreterState_Get()->config.use_peg;
if (flags & PyCF_TYPE_COMMENTS || feature_version >= 0) {
PyInterpreterState_Get()->config.use_peg = 0;
}
result = Py_CompileStringObject(str, filename, start[compile_mode], &cf, optimize);
PyInterpreterState_Get()->config.use_peg = current_use_peg;
Py_XDECREF(source_copy);
goto finally;

67
Python/compile.c
View File

@ -2152,6 +2152,55 @@ compiler_default_arguments(struct compiler *c, arguments_ty args)
return funcflags;
}
static int
forbidden_name(struct compiler *c, identifier name, expr_context_ty ctx)
{
if (ctx == Store && _PyUnicode_EqualToASCIIString(name, "__debug__")) {
compiler_error(c, "cannot assign to __debug__");
return 1;
}
return 0;
}
static int
compiler_check_debug_one_arg(struct compiler *c, arg_ty arg)
{
if (arg != NULL) {
if (forbidden_name(c, arg->arg, Store))
return 0;
}
return 1;
}
static int
compiler_check_debug_args_seq(struct compiler *c, asdl_seq *args)
{
if (args != NULL) {
for (int i = 0, n = asdl_seq_LEN(args); i < n; i++) {
if (!compiler_check_debug_one_arg(c, asdl_seq_GET(args, i)))
return 0;
}
}
return 1;
}
static int
compiler_check_debug_args(struct compiler *c, arguments_ty args)
{
if (!compiler_check_debug_args_seq(c, args->posonlyargs))
return 0;
if (!compiler_check_debug_args_seq(c, args->args))
return 0;
if (!compiler_check_debug_one_arg(c, args->vararg))
return 0;
if (!compiler_check_debug_args_seq(c, args->kwonlyargs))
return 0;
if (!compiler_check_debug_one_arg(c, args->kwarg))
return 0;
return 1;
}
static int
compiler_function(struct compiler *c, stmt_ty s, int is_async)
{
@ -2189,6 +2238,9 @@ compiler_function(struct compiler *c, stmt_ty s, int is_async)
scope_type = COMPILER_SCOPE_FUNCTION;
}
if (!compiler_check_debug_args(c, args))
return 0;
if (!compiler_decorators(c, decos))
return 0;
@ -2596,6 +2648,9 @@ compiler_lambda(struct compiler *c, expr_ty e)
arguments_ty args = e->v.Lambda.args;
assert(e->kind == Lambda_kind);
if (!compiler_check_debug_args(c, args))
return 0;
if (!name) {
name = PyUnicode_InternFromString("<lambda>");
if (!name)
@ -3505,6 +3560,9 @@ compiler_nameop(struct compiler *c, identifier name, expr_context_ty ctx)
!_PyUnicode_EqualToASCIIString(name, "True") &&
!_PyUnicode_EqualToASCIIString(name, "False"));
if (forbidden_name(c, name, ctx))
return 0;
mangled = _Py_Mangle(c->u->u_private, name);
if (!mangled)
return 0;
@ -4056,6 +4114,9 @@ validate_keywords(struct compiler *c, asdl_seq *keywords)
if (key->arg == NULL) {
continue;
}
if (forbidden_name(c, key->arg, Store)) {
return -1;
}
for (Py_ssize_t j = i + 1; j < nkeywords; j++) {
keyword_ty other = ((keyword_ty)asdl_seq_GET(keywords, j));
if (other->arg && !PyUnicode_Compare(key->arg, other->arg)) {
@ -5013,6 +5074,8 @@ compiler_visit_expr1(struct compiler *c, expr_ty e)
ADDOP_NAME(c, LOAD_ATTR, e->v.Attribute.attr, names);
break;
case Store:
if (forbidden_name(c, e->v.Attribute.attr, e->v.Attribute.ctx))
return 0;
ADDOP_NAME(c, STORE_ATTR, e->v.Attribute.attr, names);
break;
case Del:
@ -5183,6 +5246,8 @@ compiler_annassign(struct compiler *c, stmt_ty s)
}
switch (targ->kind) {
case Name_kind:
if (forbidden_name(c, targ->v.Name.id, Store))
return 0;
/* If we have a simple name in a module or class, store annotation. */
if (s->v.AnnAssign.simple &&
(c->u->u_scope_type == COMPILER_SCOPE_MODULE ||
@ -5200,6 +5265,8 @@ compiler_annassign(struct compiler *c, stmt_ty s)
}
break;
case Attribute_kind:
if (forbidden_name(c, targ->v.Attribute.attr, Store))
return 0;
if (!s->v.AnnAssign.value &&
!check_ann_expr(c, targ->v.Attribute.value)) {
return 0;

89
Python/importlib.h generated
View File

@ -1594,50 +1594,51 @@ const unsigned char _Py_M__importlib_bootstrap[] = {
0,218,1,120,90,5,119,104,101,114,101,90,9,102,114,111,
109,95,110,97,109,101,90,3,101,120,99,114,10,0,0,0,
114,10,0,0,0,114,11,0,0,0,114,215,0,0,0,9,
4,0,0,115,44,0,0,0,0,10,8,1,10,1,4,1,
12,2,4,1,28,2,8,1,14,1,10,1,2,255,8,2,
10,1,14,1,2,1,14,1,14,4,10,1,16,255,2,2,
12,1,26,1,114,215,0,0,0,99,1,0,0,0,0,0,
0,0,0,0,0,0,3,0,0,0,6,0,0,0,67,0,
0,0,115,146,0,0,0,124,0,160,0,100,1,161,1,125,
1,124,0,160,0,100,2,161,1,125,2,124,1,100,3,117,
1,114,82,124,2,100,3,117,1,114,78,124,1,124,2,106,
1,107,3,114,78,116,2,106,3,100,4,124,1,155,2,100,
5,124,2,106,1,155,2,100,6,157,5,116,4,100,7,100,
8,141,3,1,0,124,1,83,0,124,2,100,3,117,1,114,
96,124,2,106,1,83,0,116,2,106,3,100,9,116,4,100,
7,100,8,141,3,1,0,124,0,100,10,25,0,125,1,100,
11,124,0,118,1,114,142,124,1,160,5,100,12,161,1,100,
13,25,0,125,1,124,1,83,0,41,14,122,167,67,97,108,
99,117,108,97,116,101,32,119,104,97,116,32,95,95,112,97,
99,107,97,103,101,95,95,32,115,104,111,117,108,100,32,98,
101,46,10,10,32,32,32,32,95,95,112,97,99,107,97,103,
101,95,95,32,105,115,32,110,111,116,32,103,117,97,114,97,
110,116,101,101,100,32,116,111,32,98,101,32,100,101,102,105,
110,101,100,32,111,114,32,99,111,117,108,100,32,98,101,32,
115,101,116,32,116,111,32,78,111,110,101,10,32,32,32,32,
116,111,32,114,101,112,114,101,115,101,110,116,32,116,104,97,
116,32,105,116,115,32,112,114,111,112,101,114,32,118,97,108,
117,101,32,105,115,32,117,110,107,110,111,119,110,46,10,10,
32,32,32,32,114,146,0,0,0,114,106,0,0,0,78,122,
32,95,95,112,97,99,107,97,103,101,95,95,32,33,61,32,
95,95,115,112,101,99,95,95,46,112,97,114,101,110,116,32,
40,122,4,32,33,61,32,250,1,41,233,3,0,0,0,41,
1,90,10,115,116,97,99,107,108,101,118,101,108,122,89,99,
97,110,39,116,32,114,101,115,111,108,118,101,32,112,97,99,
107,97,103,101,32,102,114,111,109,32,95,95,115,112,101,99,
95,95,32,111,114,32,95,95,112,97,99,107,97,103,101,95,
95,44,32,102,97,108,108,105,110,103,32,98,97,99,107,32,
111,110,32,95,95,110,97,109,101,95,95,32,97,110,100,32,
95,95,112,97,116,104,95,95,114,1,0,0,0,114,142,0,
0,0,114,129,0,0,0,114,22,0,0,0,41,6,114,35,
0,0,0,114,131,0,0,0,114,193,0,0,0,114,194,0,
0,0,114,195,0,0,0,114,130,0,0,0,41,3,218,7,
103,108,111,98,97,108,115,114,187,0,0,0,114,96,0,0,
0,114,10,0,0,0,114,10,0,0,0,114,11,0,0,0,
218,17,95,99,97,108,99,95,95,95,112,97,99,107,97,103,
101,95,95,46,4,0,0,115,34,0,0,0,0,7,10,1,
10,1,8,1,18,1,22,2,4,254,6,3,4,1,8,1,
4,0,0,115,52,0,0,0,0,10,8,1,10,1,4,1,
12,2,4,1,4,1,2,255,4,1,8,255,10,2,8,1,
14,1,10,1,2,255,8,2,10,1,14,1,2,1,14,1,
14,4,10,1,16,255,2,2,12,1,26,1,114,215,0,0,
0,99,1,0,0,0,0,0,0,0,0,0,0,0,3,0,
0,0,6,0,0,0,67,0,0,0,115,146,0,0,0,124,
0,160,0,100,1,161,1,125,1,124,0,160,0,100,2,161,
1,125,2,124,1,100,3,117,1,114,82,124,2,100,3,117,
1,114,78,124,1,124,2,106,1,107,3,114,78,116,2,106,
3,100,4,124,1,155,2,100,5,124,2,106,1,155,2,100,
6,157,5,116,4,100,7,100,8,141,3,1,0,124,1,83,
0,124,2,100,3,117,1,114,96,124,2,106,1,83,0,116,
2,106,3,100,9,116,4,100,7,100,8,141,3,1,0,124,
0,100,10,25,0,125,1,100,11,124,0,118,1,114,142,124,
1,160,5,100,12,161,1,100,13,25,0,125,1,124,1,83,
0,41,14,122,167,67,97,108,99,117,108,97,116,101,32,119,
104,97,116,32,95,95,112,97,99,107,97,103,101,95,95,32,
115,104,111,117,108,100,32,98,101,46,10,10,32,32,32,32,
95,95,112,97,99,107,97,103,101,95,95,32,105,115,32,110,
111,116,32,103,117,97,114,97,110,116,101,101,100,32,116,111,
32,98,101,32,100,101,102,105,110,101,100,32,111,114,32,99,
111,117,108,100,32,98,101,32,115,101,116,32,116,111,32,78,
111,110,101,10,32,32,32,32,116,111,32,114,101,112,114,101,
115,101,110,116,32,116,104,97,116,32,105,116,115,32,112,114,
111,112,101,114,32,118,97,108,117,101,32,105,115,32,117,110,
107,110,111,119,110,46,10,10,32,32,32,32,114,146,0,0,
0,114,106,0,0,0,78,122,32,95,95,112,97,99,107,97,
103,101,95,95,32,33,61,32,95,95,115,112,101,99,95,95,
46,112,97,114,101,110,116,32,40,122,4,32,33,61,32,250,
1,41,233,3,0,0,0,41,1,90,10,115,116,97,99,107,
108,101,118,101,108,122,89,99,97,110,39,116,32,114,101,115,
111,108,118,101,32,112,97,99,107,97,103,101,32,102,114,111,
109,32,95,95,115,112,101,99,95,95,32,111,114,32,95,95,
112,97,99,107,97,103,101,95,95,44,32,102,97,108,108,105,
110,103,32,98,97,99,107,32,111,110,32,95,95,110,97,109,
101,95,95,32,97,110,100,32,95,95,112,97,116,104,95,95,
114,1,0,0,0,114,142,0,0,0,114,129,0,0,0,114,
22,0,0,0,41,6,114,35,0,0,0,114,131,0,0,0,
114,193,0,0,0,114,194,0,0,0,114,195,0,0,0,114,
130,0,0,0,41,3,218,7,103,108,111,98,97,108,115,114,
187,0,0,0,114,96,0,0,0,114,10,0,0,0,114,10,
0,0,0,114,11,0,0,0,218,17,95,99,97,108,99,95,
95,95,112,97,99,107,97,103,101,95,95,46,4,0,0,115,
42,0,0,0,0,7,10,1,10,1,8,1,18,1,6,1,
2,255,4,1,4,255,6,2,4,254,6,3,4,1,8,1,
6,2,6,2,4,254,6,3,8,1,8,1,14,1,114,221,
0,0,0,114,10,0,0,0,99,5,0,0,0,0,0,0,
0,0,0,0,0,9,0,0,0,5,0,0,0,67,0,0,

7
Python/importlib_external.h generated
View File

@ -481,10 +481,11 @@ const unsigned char _Py_M__importlib_bootstrap_external[] = {
108,101,118,101,108,90,13,98,97,115,101,95,102,105,108,101,
110,97,109,101,114,5,0,0,0,114,5,0,0,0,114,8,
0,0,0,218,17,115,111,117,114,99,101,95,102,114,111,109,
95,99,97,99,104,101,116,1,0,0,115,52,0,0,0,0,
95,99,97,99,104,101,116,1,0,0,115,68,0,0,0,0,
9,12,1,8,1,10,1,12,1,4,1,10,1,12,1,14,
1,16,1,4,1,4,1,12,1,8,1,18,2,10,1,8,
1,16,1,10,1,16,1,10,1,14,2,16,1,10,1,16,
1,16,1,4,1,4,1,12,1,8,1,2,1,2,255,4,
1,2,255,8,2,10,1,8,1,16,1,10,1,16,1,10,
1,4,1,2,255,8,2,16,1,10,1,4,1,2,255,10,
2,14,1,114,102,0,0,0,99,1,0,0,0,0,0,0,
0,0,0,0,0,5,0,0,0,9,0,0,0,67,0,0,
0,115,124,0,0,0,116,0,124,0,131,1,100,1,107,2,

10
Python/initconfig.c
View File

@ -68,6 +68,7 @@ static const char usage_3[] = "\
-X opt : set implementation-specific option. The following options are available:\n\
\n\
-X faulthandler: enable faulthandler\n\
-X oldparser: enable the traditional LL(1) parser; also PYTHONOLDPARSER\n\
-X showrefcount: output the total reference count and number of used\n\
memory blocks when the program finishes or after each statement in the\n\
interactive interpreter. This only works on debug builds\n\
@ -634,6 +635,7 @@ _PyConfig_InitCompatConfig(PyConfig *config)
#ifdef MS_WINDOWS
config->legacy_windows_stdio = -1;
#endif
config->use_peg = 1;
}
@ -791,6 +793,7 @@ _PyConfig_Copy(PyConfig *config, const PyConfig *config2)
COPY_ATTR(isolated);
COPY_ATTR(use_environment);
COPY_ATTR(dev_mode);
COPY_ATTR(use_peg);
COPY_ATTR(install_signal_handlers);
COPY_ATTR(use_hash_seed);
COPY_ATTR(hash_seed);
@ -894,6 +897,7 @@ config_as_dict(const PyConfig *config)
SET_ITEM_INT(isolated);
SET_ITEM_INT(use_environment);
SET_ITEM_INT(dev_mode);
SET_ITEM_INT(use_peg);
SET_ITEM_INT(install_signal_handlers);
SET_ITEM_INT(use_hash_seed);
SET_ITEM_UINT(hash_seed);
@ -1428,6 +1432,11 @@ config_read_complex_options(PyConfig *config)
config->import_time = 1;
}
if (config_get_env(config, "PYTHONOLDPARSER")
|| config_get_xoption(config, L"oldparser")) {
config->use_peg = 0;
}
PyStatus status;
if (config->tracemalloc < 0) {
status = config_init_tracemalloc(config);
@ -2507,6 +2516,7 @@ PyConfig_Read(PyConfig *config)
assert(config->isolated >= 0);
assert(config->use_environment >= 0);
assert(config->dev_mode >= 0);
assert(config->use_peg >= 0);
assert(config->install_signal_handlers >= 0);
assert(config->use_hash_seed >= 0);
assert(config->faulthandler >= 0);

54
Python/pythonrun.c
View File

@ -29,6 +29,8 @@
#include "ast.h" // PyAST_FromNodeObject()
#include "marshal.h" // PyMarshal_ReadLongFromFile()
#include <pegen_interface.h> // PyPegen_ASTFrom*
#ifdef MS_WINDOWS
# include "malloc.h" // alloca()
#endif
@ -183,6 +185,7 @@ PyRun_InteractiveOneObjectEx(FILE *fp, PyObject *filename,
PyArena *arena;
const char *ps1 = "", *ps2 = "", *enc = NULL;
int errcode = 0;
int use_peg = _PyInterpreterState_GET()->config.use_peg;
_Py_IDENTIFIER(encoding);
_Py_IDENTIFIER(__main__);
@ -235,9 +238,17 @@ PyRun_InteractiveOneObjectEx(FILE *fp, PyObject *filename,
Py_XDECREF(oenc);
return -1;
}
mod = PyParser_ASTFromFileObject(fp, filename, enc,
Py_single_input, ps1, ps2,
flags, &errcode, arena);
if (use_peg) {
mod = PyPegen_ASTFromFileObject(fp, filename, Py_single_input,
enc, ps1, ps2, &errcode, arena);
}
else {
mod = PyParser_ASTFromFileObject(fp, filename, enc,
Py_single_input, ps1, ps2,
flags, &errcode, arena);
}
Py_XDECREF(v);
Py_XDECREF(w);
Py_XDECREF(oenc);
@ -1019,6 +1030,7 @@ PyRun_StringFlags(const char *str, int start, PyObject *globals,
mod_ty mod;
PyArena *arena;
PyObject *filename;
int use_peg = _PyInterpreterState_GET()->config.use_peg;
filename = _PyUnicode_FromId(&PyId_string); /* borrowed */
if (filename == NULL)
@ -1028,7 +1040,13 @@ PyRun_StringFlags(const char *str, int start, PyObject *globals,
if (arena == NULL)
return NULL;
mod = PyParser_ASTFromStringObject(str, filename, start, flags, arena);
if (use_peg) {
mod = PyPegen_ASTFromStringObject(str, filename, start, flags, arena);
}
else {
mod = PyParser_ASTFromStringObject(str, filename, start, flags, arena);
}
if (mod != NULL)
ret = run_mod(mod, filename, globals, locals, flags, arena);
PyArena_Free(arena);
@ -1043,6 +1061,7 @@ PyRun_FileExFlags(FILE *fp, const char *filename_str, int start, PyObject *globa
mod_ty mod;
PyArena *arena = NULL;
PyObject *filename;
int use_peg = _PyInterpreterState_GET()->config.use_peg;
filename = PyUnicode_DecodeFSDefault(filename_str);
if (filename == NULL)
@ -1052,8 +1071,15 @@ PyRun_FileExFlags(FILE *fp, const char *filename_str, int start, PyObject *globa
if (arena == NULL)
goto exit;
mod = PyParser_ASTFromFileObject(fp, filename, NULL, start, 0, 0,
flags, NULL, arena);
if (use_peg) {
mod = PyPegen_ASTFromFileObject(fp, filename, start, NULL, NULL, NULL,
NULL, arena);
}
else {
mod = PyParser_ASTFromFileObject(fp, filename, NULL, start, 0, 0,
flags, NULL, arena);
}
if (closeit)
fclose(fp);
if (mod == NULL) {
@ -1196,11 +1222,17 @@ Py_CompileStringObject(const char *str, PyObject *filename, int start,
{
PyCodeObject *co;
mod_ty mod;
int use_peg = _PyInterpreterState_GET()->config.use_peg;
PyArena *arena = PyArena_New();
if (arena == NULL)
return NULL;
mod = PyParser_ASTFromStringObject(str, filename, start, flags, arena);
if (use_peg) {
mod = PyPegen_ASTFromStringObject(str, filename, start, flags, arena);
}
else {
mod = PyParser_ASTFromStringObject(str, filename, start, flags, arena);
}
if (mod == NULL) {
PyArena_Free(arena);
return NULL;
@ -1297,13 +1329,19 @@ _Py_SymtableStringObjectFlags(const char *str, PyObject *filename, int start, Py
{
struct symtable *st;
mod_ty mod;
int use_peg = _PyInterpreterState_GET()->config.use_peg;
PyArena *arena;
arena = PyArena_New();
if (arena == NULL)
return NULL;
mod = PyParser_ASTFromStringObject(str, filename, start, flags, arena);
if (use_peg) {
mod = PyPegen_ASTFromStringObject(str, filename, start, flags, arena);
}
else {
mod = PyParser_ASTFromStringObject(str, filename, start, flags, arena);
}
if (mod == NULL) {
PyArena_Free(arena);
return NULL;

4
Python/sysmodule.c
View File

@ -2427,6 +2427,7 @@ static PyStructSequence_Field flags_fields[] = {
{"inspect", "-i"},
{"interactive", "-i"},
{"optimize", "-O or -OO"},
{"use_peg", "-p old or -p new"},
{"dont_write_bytecode", "-B"},
{"no_user_site", "-s"},
{"no_site", "-S"},
@ -2447,7 +2448,7 @@ static PyStructSequence_Desc flags_desc = {
"sys.flags", /* name */
flags__doc__, /* doc */
flags_fields, /* fields */
15
16
};
static PyObject*
@ -2470,6 +2471,7 @@ make_flags(PyThreadState *tstate)
SetFlag(config->inspect);
SetFlag(config->interactive);
SetFlag(config->optimization_level);
SetFlag(config->use_peg);
SetFlag(!config->write_bytecode);
SetFlag(!config->user_site_directory);
SetFlag(!config->site_import);

2
Tools/README
View File

@ -23,6 +23,8 @@ msi Support for packaging Python as an MSI package on Windows.
parser Un-parsing tool to generate code from an AST.
peg_generator PEG-based parser generator (pegen) used for new parser.
pynche A Tkinter-based color editor.
scripts A number of useful single-file programs, e.g. tabnanny.py

17
Tools/peg_generator/.clang-format Normal file
View File

@ -0,0 +1,17 @@
# A clang-format style that approximates Python's PEP 7
BasedOnStyle: Google
AlwaysBreakAfterReturnType: All
AllowShortIfStatementsOnASingleLine: false
AlignAfterOpenBracket: Align
BreakBeforeBraces: Stroustrup
ColumnLimit: 95
DerivePointerAlignment: false
IndentWidth: 4
Language: Cpp
PointerAlignment: Right
ReflowComments: true
SpaceBeforeParens: ControlStatements
SpacesInParentheses: false
TabWidth: 4
UseTab: Never
SortIncludes: false

3
Tools/peg_generator/.gitignore vendored Normal file
View File

@ -0,0 +1,3 @@
peg_extension/parse.c
data/xxl.py
@data

116
Tools/peg_generator/Makefile Normal file
View File

@ -0,0 +1,116 @@
UNAME_S := $(shell uname -s)
ifeq ($(UNAME_S),Linux)
PYTHON ?= ../../python
endif
ifeq ($(UNAME_S),Darwin)
PYTHON ?= ../../python.exe
endif
CPYTHON ?= ../../Lib
MYPY ?= mypy
GRAMMAR = ../../Grammar/python.gram
TESTFILE = data/cprog.py
TIMEFILE = data/xxl.py
TESTDIR = .
TESTFLAGS = --short
data/xxl.py:
$(PYTHON) -m zipfile -e data/xxl.zip data
build: peg_extension/parse.c
peg_extension/parse.c: $(GRAMMAR) pegen/*.py peg_extension/peg_extension.c ../../Parser/pegen/pegen.c ../../Parser/pegen/parse_string.c ../../Parser/pegen/*.h pegen/grammar_parser.py
$(PYTHON) -m pegen -q -c $(GRAMMAR) -o peg_extension/parse.c --compile-extension
clean:
-rm -f peg_extension/*.o peg_extension/*.so peg_extension/parse.c
-rm -f data/xxl.py
dump: peg_extension/parse.c
cat -n $(TESTFILE)
$(PYTHON) -c "from peg_extension import parse; import ast; t = parse.parse_file('$(TESTFILE)', mode=1); print(ast.dump(t))"
regen-metaparser: pegen/metagrammar.gram pegen/*.py
$(PYTHON) -m pegen -q -c pegen/metagrammar.gram -o pegen/grammar_parser.py
# Note: These targets really depend on the generated shared object in peg_extension/parse.*.so but
# this has different names in different systems so we are abusing the implicit dependency on
# parse.c by the use of --compile-extension.
.PHONY: test
test: run
run: peg_extension/parse.c
$(PYTHON) -c "from peg_extension import parse; t = parse.parse_file('$(TESTFILE)'); exec(t)"
compile: peg_extension/parse.c
$(PYTHON) -c "from peg_extension import parse; t = parse.parse_file('$(TESTFILE)', mode=2)"
parse: peg_extension/parse.c
$(PYTHON) -c "from peg_extension import parse; t = parse.parse_file('$(TESTFILE)', mode=1)"
check: peg_extension/parse.c
$(PYTHON) -c "from peg_extension import parse; t = parse.parse_file('$(TESTFILE)', mode=0)"
stats: peg_extension/parse.c data/xxl.py
$(PYTHON) -c "from peg_extension import parse; t = parse.parse_file('$(TIMEFILE)', mode=0); parse.dump_memo_stats()" >@data
$(PYTHON) scripts/joinstats.py @data
time: time_compile
time_compile: peg_extension/parse.c data/xxl.py
$(PYTHON) scripts/benchmark.py --parser=pegen --target=xxl compile
time_parse: peg_extension/parse.c data/xxl.py
$(PYTHON) scripts/benchmark.py --parser=pegen --target=xxl parse
time_check: peg_extension/parse.c data/xxl.py
$(PYTHON) scripts/benchmark.py --parser=pegen --target=xxl check
time_stdlib: time_stdlib_compile
time_stdlib_compile: data/xxl.py
$(PYTHON) scripts/benchmark.py --parser=cpython --target=xxl compile
time_stdlib_parse: data/xxl.py
$(PYTHON) scripts/benchmark.py --parser=cpython --target=xxl parse
test_local:
$(PYTHON) scripts/test_parse_directory.py \
-g $(GRAMMAR) \
-d $(TESTDIR) \
$(TESTFLAGS) \
--exclude "*/failset/*" \
--exclude "*/failset/**" \
--exclude "*/failset/**/*"
test_global: $(CPYTHON)
$(PYTHON) scripts/test_parse_directory.py \
-g $(GRAMMAR) \
-d $(CPYTHON) \
$(TESTFLAGS) \
--exclude "*/test2to3/*" \
--exclude "*/test2to3/**/*" \
--exclude "*/bad*" \
--exclude "*/lib2to3/tests/data/*"
mypy: regen-metaparser
$(MYPY) # For list of files, see mypy.ini
format-python:
black pegen scripts
bench:
$(PYTHON) scripts/benchmark.py --parser=pegen --target=stdlib check
format: format-python
find_max_nesting:
$(PYTHON) scripts/find_max_nesting.py
tags: TAGS
TAGS: pegen/*.py test/test_pegen.py
etags pegen/*.py test/test_pegen.py

10
Tools/peg_generator/data/cprog.py Normal file
View File

@ -0,0 +1,10 @@
if 1:
print("Hello " + "world")
if 0:
print("then")
print("clause")
elif 1:
pass
elif 1:
pass
else: print("else-clause")

BIN
Tools/peg_generator/data/xxl.zip Normal file
View File

Binary file not shown.

26
Tools/peg_generator/mypy.ini Normal file
View File

@ -0,0 +1,26 @@
[mypy]
files = pegen, scripts
follow_imports = error
no_implicit_optional = True
strict_optional = True
#check_untyped_defs = True
disallow_untyped_calls = True
disallow_untyped_defs = True
disallow_any_generics = true
disallow_any_unimported = True
disallow_incomplete_defs = True
disallow_subclassing_any = True
warn_unused_configs = True
warn_unused_ignores = true
warn_redundant_casts = true
warn_no_return = True
show_traceback = True
show_error_codes = True
[mypy-pegen.grammar_parser]
strict_optional = False

153
Tools/peg_generator/peg_extension/peg_extension.c Normal file
View File

@ -0,0 +1,153 @@
#include "pegen.h"
PyObject *
_build_return_object(mod_ty module, int mode, PyObject *filename_ob, PyArena *arena)
{
PyObject *result = NULL;
if (mode == 2) {
result = (PyObject *)PyAST_CompileObject(module, filename_ob, NULL, -1, arena);
} else if (mode == 1) {
result = PyAST_mod2obj(module);
} else {
result = Py_None;
Py_INCREF(result);
}
return result;
}
static PyObject *
parse_file(PyObject *self, PyObject *args, PyObject *kwds)
{
static char *keywords[] = {"file", "mode", NULL};
const char *filename;
int mode = 2;
if (!PyArg_ParseTupleAndKeywords(args, kwds, "s|i", keywords, &filename, &mode)) {
return NULL;
}
if (mode < 0 || mode > 2) {
return PyErr_Format(PyExc_ValueError, "Bad mode, must be 0 <= mode <= 2");
}
PyArena *arena = PyArena_New();
if (arena == NULL) {
return NULL;
}
PyObject *result = NULL;
PyObject *filename_ob = PyUnicode_FromString(filename);
if (filename_ob == NULL) {
goto error;
}
mod_ty res = _PyPegen_run_parser_from_file(filename, Py_file_input, filename_ob, arena);
if (res == NULL) {
goto error;
}
result = _build_return_object(res, mode, filename_ob, arena);
error:
Py_XDECREF(filename_ob);
PyArena_Free(arena);
return result;
}
static PyObject *
parse_string(PyObject *self, PyObject *args, PyObject *kwds)
{
static char *keywords[] = {"str", "mode", NULL};
const char *the_string;
int mode = 2;
if (!PyArg_ParseTupleAndKeywords(args, kwds, "s|i", keywords, &the_string, &mode)) {
return NULL;
}
if (mode < 0 || mode > 2) {
return PyErr_Format(PyExc_ValueError, "Bad mode, must be 0 <= mode <= 2");
}
PyArena *arena = PyArena_New();
if (arena == NULL) {
return NULL;
}
PyObject *result = NULL;
PyObject *filename_ob = PyUnicode_FromString("<string>");
if (filename_ob == NULL) {
goto error;
}
mod_ty res = _PyPegen_run_parser_from_string(the_string, Py_file_input, filename_ob,
PyCF_IGNORE_COOKIE, arena);
if (res == NULL) {
goto error;
}
result = _build_return_object(res, mode, filename_ob, arena);
error:
Py_XDECREF(filename_ob);
PyArena_Free(arena);
return result;
}
static PyObject *
clear_memo_stats()
{
_PyPegen_clear_memo_statistics();
Py_RETURN_NONE;
}
static PyObject *
get_memo_stats()
{
return _PyPegen_get_memo_statistics();
}
// TODO: Write to Python's sys.stdout instead of C's stdout.
static PyObject *
dump_memo_stats()
{
PyObject *list = _PyPegen_get_memo_statistics();
if (list == NULL) {
return NULL;
}
Py_ssize_t len = PyList_Size(list);
for (Py_ssize_t i = 0; i < len; i++) {
PyObject *value = PyList_GetItem(list, i); // Borrowed reference.
long count = PyLong_AsLong(value);
if (count < 0) {
break;
}
if (count > 0) {
printf("%4ld %9ld\n", i, count);
}
}
Py_DECREF(list);
Py_RETURN_NONE;
}
static PyMethodDef ParseMethods[] = {
{"parse_file", (PyCFunction)(void(*)(void))parse_file, METH_VARARGS|METH_KEYWORDS, "Parse a file."},
{"parse_string", (PyCFunction)(void(*)(void))parse_string, METH_VARARGS|METH_KEYWORDS, "Parse a string."},
{"clear_memo_stats", clear_memo_stats, METH_NOARGS},
{"dump_memo_stats", dump_memo_stats, METH_NOARGS},
{"get_memo_stats", get_memo_stats, METH_NOARGS},
{NULL, NULL, 0, NULL} /* Sentinel */
};
static struct PyModuleDef parsemodule = {
PyModuleDef_HEAD_INIT,
.m_name = "parse",
.m_doc = "A parser.",
.m_methods = ParseMethods,
};
PyMODINIT_FUNC
PyInit_parse(void)
{
return PyModule_Create(&parsemodule);
}

0
Tools/peg_generator/pegen/__init__.py Normal file
View File

136
Tools/peg_generator/pegen/__main__.py Executable file
View File

@ -0,0 +1,136 @@
#!/usr/bin/env python3.8
"""pegen -- PEG Generator.
Search the web for PEG Parsers for reference.
"""
import argparse
import sys
import time
import token
import traceback
from typing import Final
from pegen.build import build_parser_and_generator
from pegen.testutil import print_memstats
argparser = argparse.ArgumentParser(
prog="pegen", description="Experimental PEG-like parser generator"
)
argparser.add_argument("-q", "--quiet", action="store_true", help="Don't print the parsed grammar")
argparser.add_argument(
"-v",
"--verbose",
action="count",
default=0,
help="Print timing stats; repeat for more debug output",
)
argparser.add_argument(
"-c", "--cpython", action="store_true", help="Generate C code for inclusion into CPython"
)
argparser.add_argument(
"--compile-extension",
action="store_true",
help="Compile generated C code into an extension module",
)
argparser.add_argument(
"-o",
"--output",
metavar="OUT",
help="Where to write the generated parser (default parse.py or parse.c)",
)
argparser.add_argument("filename", help="Grammar description")
argparser.add_argument(
"--optimized", action="store_true", help="Compile the extension in optimized mode"
)
argparser.add_argument(
"--skip-actions", action="store_true", help="Suppress code emission for rule actions",
)
def main() -> None:
args = argparser.parse_args()
verbose = args.verbose
verbose_tokenizer = verbose >= 3
verbose_parser = verbose == 2 or verbose >= 4
t0 = time.time()
output_file = args.output
if not output_file:
if args.cpython:
output_file = "parse.c"
else:
output_file = "parse.py"
try:
grammar, parser, tokenizer, gen = build_parser_and_generator(
args.filename,
output_file,
args.compile_extension,
verbose_tokenizer,
verbose_parser,
args.verbose,
keep_asserts_in_extension=False if args.optimized else True,
skip_actions=args.skip_actions,
)
except Exception as err:
if args.verbose:
raise # Show traceback
traceback.print_exception(err.__class__, err, None)
sys.stderr.write("For full traceback, use -v\n")
sys.exit(1)
if not args.quiet:
if args.verbose:
print("Raw Grammar:")
for line in repr(grammar).splitlines():
print(" ", line)
print("Clean Grammar:")
for line in str(grammar).splitlines():
print(" ", line)
if args.verbose:
print("First Graph:")
for src, dsts in gen.first_graph.items():
print(f" {src} -> {', '.join(dsts)}")
print("First SCCS:")
for scc in gen.first_sccs:
print(" ", scc, end="")
if len(scc) > 1:
print(
" # Indirectly left-recursive; leaders:",
{name for name in scc if grammar.rules[name].leader},
)
else:
name = next(iter(scc))
if name in gen.first_graph[name]:
print(" # Left-recursive")
else:
print()
t1 = time.time()
if args.verbose:
dt = t1 - t0
diag = tokenizer.diagnose()
nlines = diag.end[0]
if diag.type == token.ENDMARKER:
nlines -= 1
print(f"Total time: {dt:.3f} sec; {nlines} lines", end="")
if dt:
print(f"; {nlines / dt:.0f} lines/sec")
else:
print()
print("Caches sizes:")
print(f" token array : {len(tokenizer._tokens):10}")
print(f" cache : {len(parser._cache):10}")
if not print_memstats():
print("(Can't find psutil; install it for memory stats.)")
if __name__ == "__main__":
main()

169
Tools/peg_generator/pegen/build.py Normal file
View File

@ -0,0 +1,169 @@
import pathlib
import shutil
import tokenize
from typing import Optional, Tuple
import distutils.log
from distutils.core import Distribution, Extension
from distutils.command.clean import clean # type: ignore
from distutils.command.build_ext import build_ext # type: ignore
from pegen.c_generator import CParserGenerator
from pegen.grammar import Grammar
from pegen.grammar_parser import GeneratedParser as GrammarParser
from pegen.parser import Parser
from pegen.parser_generator import ParserGenerator
from pegen.python_generator import PythonParserGenerator
from pegen.tokenizer import Tokenizer
MOD_DIR = pathlib.Path(__file__).parent
def compile_c_extension(
generated_source_path: str,
build_dir: Optional[str] = None,
verbose: bool = False,
keep_asserts: bool = True,
) -> str:
"""Compile the generated source for a parser generator into an extension module.
The extension module will be generated in the same directory as the provided path
for the generated source, with the same basename (in addition to extension module
metadata). For example, for the source mydir/parser.c the generated extension
in a darwin system with python 3.8 will be mydir/parser.cpython-38-darwin.so.
If *build_dir* is provided, that path will be used as the temporary build directory
of distutils (this is useful in case you want to use a temporary directory).
"""
if verbose:
distutils.log.set_verbosity(distutils.log.DEBUG)
source_file_path = pathlib.Path(generated_source_path)
extension_name = source_file_path.stem
extra_compile_args = []
if keep_asserts:
extra_compile_args.append("-UNDEBUG")
extension = [
Extension(
extension_name,
sources=[
str(MOD_DIR.parent.parent.parent / "Python" / "Python-ast.c"),
str(MOD_DIR.parent.parent.parent / "Python" / "asdl.c"),
str(MOD_DIR.parent.parent.parent / "Parser" / "tokenizer.c"),
str(MOD_DIR.parent.parent.parent / "Parser" / "pegen" / "pegen.c"),
str(MOD_DIR.parent.parent.parent / "Parser" / "pegen" / "parse_string.c"),
str(MOD_DIR.parent / "peg_extension" / "peg_extension.c"),
generated_source_path,
],
include_dirs=[
str(MOD_DIR.parent.parent.parent / "Include" / "internal"),
str(MOD_DIR.parent.parent.parent / "Parser"),
str(MOD_DIR.parent.parent.parent / "Parser" / "pegen"),
],
extra_compile_args=extra_compile_args,
)
]
dist = Distribution({"name": extension_name, "ext_modules": extension})
cmd = build_ext(dist)
cmd.inplace = True
if build_dir:
cmd.build_temp = build_dir
cmd.ensure_finalized()
cmd.run()
extension_path = source_file_path.parent / cmd.get_ext_filename(extension_name)
shutil.move(cmd.get_ext_fullpath(extension_name), extension_path)
cmd = clean(dist)
cmd.finalize_options()
cmd.run()
return extension_path
def build_parser(
grammar_file: str, verbose_tokenizer: bool = False, verbose_parser: bool = False
) -> Tuple[Grammar, Parser, Tokenizer]:
with open(grammar_file) as file:
tokenizer = Tokenizer(tokenize.generate_tokens(file.readline), verbose=verbose_tokenizer)
parser = GrammarParser(tokenizer, verbose=verbose_parser)
grammar = parser.start()
if not grammar:
raise parser.make_syntax_error(grammar_file)
return grammar, parser, tokenizer
def build_generator(
tokenizer: Tokenizer,
grammar: Grammar,
grammar_file: str,
output_file: str,
compile_extension: bool = False,
verbose_c_extension: bool = False,
keep_asserts_in_extension: bool = True,
skip_actions: bool = False,
) -> ParserGenerator:
# TODO: Allow other extensions; pass the output type as an argument.
if not output_file.endswith((".c", ".py")):
raise RuntimeError("Your output file must either be a .c or .py file")
with open(output_file, "w") as file:
gen: ParserGenerator
if output_file.endswith(".c"):
gen = CParserGenerator(grammar, file, skip_actions=skip_actions)
elif output_file.endswith(".py"):
gen = PythonParserGenerator(grammar, file) # TODO: skip_actions
else:
assert False # Should have been checked above
gen.generate(grammar_file)
if compile_extension and output_file.endswith(".c"):
compile_c_extension(
output_file, verbose=verbose_c_extension, keep_asserts=keep_asserts_in_extension
)
return gen
def build_parser_and_generator(
grammar_file: str,
output_file: str,
compile_extension: bool = False,
verbose_tokenizer: bool = False,
verbose_parser: bool = False,
verbose_c_extension: bool = False,
keep_asserts_in_extension: bool = True,
skip_actions: bool = False,
) -> Tuple[Grammar, Parser, Tokenizer, ParserGenerator]:
"""Generate rules, parser, tokenizer, parser generator for a given grammar
Args:
grammar_file (string): Path for the grammar file
output_file (string): Path for the output file
compile_extension (bool, optional): Whether to compile the C extension.
Defaults to False.
verbose_tokenizer (bool, optional): Whether to display additional output
when generating the tokenizer. Defaults to False.
verbose_parser (bool, optional): Whether to display additional output
when generating the parser. Defaults to False.
verbose_c_extension (bool, optional): Whether to display additional
output when compiling the C extension . Defaults to False.
keep_asserts_in_extension (bool, optional): Whether to keep the assert statements
when compiling the extension module. Defaults to True.
skip_actions (bool, optional): Whether to pretend no rule has any actions.
"""
grammar, parser, tokenizer = build_parser(grammar_file, verbose_tokenizer, verbose_parser)
gen = build_generator(
tokenizer,
grammar,
grammar_file,
output_file,
compile_extension,
verbose_c_extension,
keep_asserts_in_extension,
skip_actions=skip_actions,
)
return grammar, parser, tokenizer, gen

605
Tools/peg_generator/pegen/c_generator.py Normal file
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@ -0,0 +1,605 @@
import ast
import re
from typing import Any, cast, Dict, IO, Optional, List, Text, Tuple
from pegen.grammar import (
Cut,
GrammarVisitor,
Rhs,
Alt,
NamedItem,
NameLeaf,
StringLeaf,
Lookahead,
PositiveLookahead,
NegativeLookahead,
Opt,
Repeat0,
Repeat1,
Gather,
Group,
Rule,
)
from pegen import grammar
from pegen.parser_generator import dedupe, ParserGenerator
from pegen.tokenizer import exact_token_types
EXTENSION_PREFIX = """\
#include "pegen.h"
"""
EXTENSION_SUFFIX = """
void *
_PyPegen_parse(Parser *p)
{
// Initialize keywords
p->keywords = reserved_keywords;
p->n_keyword_lists = n_keyword_lists;
return start_rule(p);
}
"""
class CCallMakerVisitor(GrammarVisitor):
def __init__(self, parser_generator: ParserGenerator):
self.gen = parser_generator
self.cache: Dict[Any, Any] = {}
self.keyword_cache: Dict[str, int] = {}
def keyword_helper(self, keyword: str) -> Tuple[str, str]:
if keyword not in self.keyword_cache:
self.keyword_cache[keyword] = self.gen.keyword_type()
return "keyword", f"_PyPegen_expect_token(p, {self.keyword_cache[keyword]})"
def visit_NameLeaf(self, node: NameLeaf) -> Tuple[str, str]:
name = node.value
if name in ("NAME", "NUMBER", "STRING"):
name = name.lower()
return f"{name}_var", f"_PyPegen_{name}_token(p)"
if name in ("NEWLINE", "DEDENT", "INDENT", "ENDMARKER", "ASYNC", "AWAIT"):
name = name.lower()
return f"{name}_var", f"_PyPegen_{name}_token(p)"
return f"{name}_var", f"{name}_rule(p)"
def visit_StringLeaf(self, node: StringLeaf) -> Tuple[str, str]:
val = ast.literal_eval(node.value)
if re.match(r"[a-zA-Z_]\w*\Z", val): # This is a keyword
return self.keyword_helper(val)
else:
assert val in exact_token_types, f"{node.value} is not a known literal"
type = exact_token_types[val]
return "literal", f"_PyPegen_expect_token(p, {type})"
def visit_Rhs(self, node: Rhs) -> Tuple[Optional[str], str]:
if node in self.cache:
return self.cache[node]
if len(node.alts) == 1 and len(node.alts[0].items) == 1:
self.cache[node] = self.visit(node.alts[0].items[0])
else:
name = self.gen.name_node(node)
self.cache[node] = f"{name}_var", f"{name}_rule(p)"
return self.cache[node]
def visit_NamedItem(self, node: NamedItem) -> Tuple[Optional[str], str]:
name, call = self.visit(node.item)
if node.name:
name = node.name
return name, call
def lookahead_call_helper(self, node: Lookahead, positive: int) -> Tuple[None, str]:
name, call = self.visit(node.node)
func, args = call.split("(", 1)
assert args[-1] == ")"
args = args[:-1]
if not args.startswith("p,"):
return None, f"_PyPegen_lookahead({positive}, {func}, {args})"
elif args[2:].strip().isalnum():
return None, f"_PyPegen_lookahead_with_int({positive}, {func}, {args})"
else:
return None, f"_PyPegen_lookahead_with_string({positive}, {func}, {args})"
def visit_PositiveLookahead(self, node: PositiveLookahead) -> Tuple[None, str]:
return self.lookahead_call_helper(node, 1)
def visit_NegativeLookahead(self, node: NegativeLookahead) -> Tuple[None, str]:
return self.lookahead_call_helper(node, 0)
def visit_Opt(self, node: Opt) -> Tuple[str, str]:
name, call = self.visit(node.node)
return "opt_var", f"{call}, 1" # Using comma operator!
def visit_Repeat0(self, node: Repeat0) -> Tuple[str, str]:
if node in self.cache:
return self.cache[node]
name = self.gen.name_loop(node.node, False)
self.cache[node] = f"{name}_var", f"{name}_rule(p)"
return self.cache[node]
def visit_Repeat1(self, node: Repeat1) -> Tuple[str, str]:
if node in self.cache:
return self.cache[node]
name = self.gen.name_loop(node.node, True)
self.cache[node] = f"{name}_var", f"{name}_rule(p)"
return self.cache[node]
def visit_Gather(self, node: Gather) -> Tuple[str, str]:
if node in self.cache:
return self.cache[node]
name = self.gen.name_gather(node)
self.cache[node] = f"{name}_var", f"{name}_rule(p)"
return self.cache[node]
def visit_Group(self, node: Group) -> Tuple[Optional[str], str]:
return self.visit(node.rhs)
def visit_Cut(self, node: Cut) -> Tuple[str, str]:
return "cut_var", "1"
class CParserGenerator(ParserGenerator, GrammarVisitor):
def __init__(
self,
grammar: grammar.Grammar,
file: Optional[IO[Text]],
debug: bool = False,
skip_actions: bool = False,
):
super().__init__(grammar, file)
self.callmakervisitor: CCallMakerVisitor = CCallMakerVisitor(self)
self._varname_counter = 0
self.debug = debug
self.skip_actions = skip_actions
def unique_varname(self, name: str = "tmpvar") -> str:
new_var = name + "_" + str(self._varname_counter)
self._varname_counter += 1
return new_var
def call_with_errorcheck_return(self, call_text: str, returnval: str) -> None:
error_var = self.unique_varname()
self.print(f"int {error_var} = {call_text};")
self.print(f"if ({error_var}) {{")
with self.indent():
self.print(f"return {returnval};")
self.print(f"}}")
def call_with_errorcheck_goto(self, call_text: str, goto_target: str) -> None:
error_var = self.unique_varname()
self.print(f"int {error_var} = {call_text};")
self.print(f"if ({error_var}) {{")
with self.indent():
self.print(f"goto {goto_target};")
self.print(f"}}")
def out_of_memory_return(
self, expr: str, returnval: str, message: str = "Parser out of memory", cleanup_code=None
) -> None:
self.print(f"if ({expr}) {{")
with self.indent():
self.print(f'PyErr_Format(PyExc_MemoryError, "{message}");')
if cleanup_code is not None:
self.print(cleanup_code)
self.print(f"return {returnval};")
self.print(f"}}")
def out_of_memory_goto(
self, expr: str, goto_target: str, message: str = "Parser out of memory"
) -> None:
self.print(f"if ({expr}) {{")
with self.indent():
self.print(f'PyErr_Format(PyExc_MemoryError, "{message}");')
self.print(f"goto {goto_target};")
self.print(f"}}")
def generate(self, filename: str) -> None:
self.collect_todo()
self.print(f"// @generated by pegen.py from {filename}")
header = self.grammar.metas.get("header", EXTENSION_PREFIX)
if header:
self.print(header.rstrip("\n"))
subheader = self.grammar.metas.get("subheader", "")
if subheader:
self.print(subheader)
self._setup_keywords()
for i, (rulename, rule) in enumerate(self.todo.items(), 1000):
comment = " // Left-recursive" if rule.left_recursive else ""
self.print(f"#define {rulename}_type {i}{comment}")
self.print()
for rulename, rule in self.todo.items():
if rule.is_loop() or rule.is_gather():
type = "asdl_seq *"
elif rule.type:
type = rule.type + " "
else:
type = "void *"
self.print(f"static {type}{rulename}_rule(Parser *p);")
self.print()
while self.todo:
for rulename, rule in list(self.todo.items()):
del self.todo[rulename]
self.print()
if rule.left_recursive:
self.print("// Left-recursive")
self.visit(rule)
if self.skip_actions:
mode = 0
else:
mode = int(self.rules["start"].type == "mod_ty") if "start" in self.rules else 1
if mode == 1 and self.grammar.metas.get("bytecode"):
mode += 1
modulename = self.grammar.metas.get("modulename", "parse")
trailer = self.grammar.metas.get("trailer", EXTENSION_SUFFIX)
keyword_cache = self.callmakervisitor.keyword_cache
if trailer:
self.print(trailer.rstrip("\n") % dict(mode=mode, modulename=modulename))
def _group_keywords_by_length(self) -> Dict[int, List[Tuple[str, int]]]:
groups: Dict[int, List[Tuple[str, int]]] = {}
for keyword_str, keyword_type in self.callmakervisitor.keyword_cache.items():
length = len(keyword_str)
if length in groups:
groups[length].append((keyword_str, keyword_type))
else:
groups[length] = [(keyword_str, keyword_type)]
return groups
def _setup_keywords(self) -> None:
keyword_cache = self.callmakervisitor.keyword_cache
n_keyword_lists = (
len(max(keyword_cache.keys(), key=len)) + 1 if len(keyword_cache) > 0 else 0
)
self.print(f"static const int n_keyword_lists = {n_keyword_lists};")
groups = self._group_keywords_by_length()
self.print("static KeywordToken *reserved_keywords[] = {")
with self.indent():
num_groups = max(groups) + 1 if groups else 1
for keywords_length in range(num_groups):
if keywords_length not in groups.keys():
self.print("NULL,")
else:
self.print("(KeywordToken[]) {")
with self.indent():
for keyword_str, keyword_type in groups[keywords_length]:
self.print(f'{{"{keyword_str}", {keyword_type}}},')
self.print("{NULL, -1},")
self.print("},")
self.print("};")
def _set_up_token_start_metadata_extraction(self) -> None:
self.print("if (p->mark == p->fill && _PyPegen_fill_token(p) < 0) {")
with self.indent():
self.print("p->error_indicator = 1;")
self.print("return NULL;")
self.print("}")
self.print("int start_lineno = p->tokens[mark]->lineno;")
self.print("UNUSED(start_lineno); // Only used by EXTRA macro")
self.print("int start_col_offset = p->tokens[mark]->col_offset;")
self.print("UNUSED(start_col_offset); // Only used by EXTRA macro")
def _set_up_token_end_metadata_extraction(self) -> None:
self.print("Token *token = _PyPegen_get_last_nonnwhitespace_token(p);")
self.print("if (token == NULL) {")
with self.indent():
self.print("return NULL;")
self.print("}")
self.print(f"int end_lineno = token->end_lineno;")
self.print("UNUSED(end_lineno); // Only used by EXTRA macro")
self.print(f"int end_col_offset = token->end_col_offset;")
self.print("UNUSED(end_col_offset); // Only used by EXTRA macro")
def _set_up_rule_memoization(self, node: Rule, result_type: str) -> None:
self.print("{")
with self.indent():
self.print(f"{result_type} res = NULL;")
self.print(f"if (_PyPegen_is_memoized(p, {node.name}_type, &res))")
with self.indent():
self.print("return res;")
self.print("int mark = p->mark;")
self.print("int resmark = p->mark;")
self.print("while (1) {")
with self.indent():
self.call_with_errorcheck_return(
f"_PyPegen_update_memo(p, mark, {node.name}_type, res)", "res"
)
self.print("p->mark = mark;")
self.print(f"void *raw = {node.name}_raw(p);")
self.print("if (raw == NULL || p->mark <= resmark)")
with self.indent():
self.print("break;")
self.print("resmark = p->mark;")
self.print("res = raw;")
self.print("}")
self.print("p->mark = resmark;")
self.print("return res;")
self.print("}")
self.print(f"static {result_type}")
self.print(f"{node.name}_raw(Parser *p)")
def _should_memoize(self, node: Rule) -> bool:
return node.memo and not node.left_recursive
def _handle_default_rule_body(self, node: Rule, rhs: Rhs, result_type: str) -> None:
memoize = self._should_memoize(node)
with self.indent():
self.print("if (p->error_indicator) {")
with self.indent():
self.print("return NULL;")
self.print("}")
self.print(f"{result_type} res = NULL;")
if memoize:
self.print(f"if (_PyPegen_is_memoized(p, {node.name}_type, &res))")
with self.indent():
self.print("return res;")
self.print("int mark = p->mark;")
if any(alt.action and "EXTRA" in alt.action for alt in rhs.alts):
self._set_up_token_start_metadata_extraction()
self.visit(
rhs,
is_loop=False,
is_gather=node.is_gather(),
rulename=node.name if memoize else None,
)
if self.debug:
self.print(f'fprintf(stderr, "Fail at %d: {node.name}\\n", p->mark);')
self.print("res = NULL;")
self.print(" done:")
with self.indent():
if memoize:
self.print(f"_PyPegen_insert_memo(p, mark, {node.name}_type, res);")
self.print("return res;")
def _handle_loop_rule_body(self, node: Rule, rhs: Rhs) -> None:
memoize = self._should_memoize(node)
is_repeat1 = node.name.startswith("_loop1")
with self.indent():
self.print("if (p->error_indicator) {")
with self.indent():
self.print("return NULL;")
self.print("}")
self.print(f"void *res = NULL;")
if memoize:
self.print(f"if (_PyPegen_is_memoized(p, {node.name}_type, &res))")
with self.indent():
self.print("return res;")
self.print("int mark = p->mark;")
self.print("int start_mark = p->mark;")
self.print("void **children = PyMem_Malloc(sizeof(void *));")
self.out_of_memory_return(f"!children", "NULL")
self.print("ssize_t children_capacity = 1;")
self.print("ssize_t n = 0;")
if any(alt.action and "EXTRA" in alt.action for alt in rhs.alts):
self._set_up_token_start_metadata_extraction()
self.visit(
rhs,
is_loop=True,
is_gather=node.is_gather(),
rulename=node.name if memoize else None,
)
if is_repeat1:
self.print("if (n == 0) {")
with self.indent():
self.print("PyMem_Free(children);")
self.print("return NULL;")
self.print("}")
self.print("asdl_seq *seq = _Py_asdl_seq_new(n, p->arena);")
self.out_of_memory_return(
f"!seq",
"NULL",
message=f"asdl_seq_new {node.name}",
cleanup_code="PyMem_Free(children);",
)
self.print("for (int i = 0; i < n; i++) asdl_seq_SET(seq, i, children[i]);")
self.print("PyMem_Free(children);")
if node.name:
self.print(f"_PyPegen_insert_memo(p, start_mark, {node.name}_type, seq);")
self.print("return seq;")
def visit_Rule(self, node: Rule) -> None:
is_loop = node.is_loop()
is_gather = node.is_gather()
rhs = node.flatten()
if is_loop or is_gather:
result_type = "asdl_seq *"
elif node.type:
result_type = node.type
else:
result_type = "void *"
for line in str(node).splitlines():
self.print(f"// {line}")
if node.left_recursive and node.leader:
self.print(f"static {result_type} {node.name}_raw(Parser *);")
self.print(f"static {result_type}")
self.print(f"{node.name}_rule(Parser *p)")
if node.left_recursive and node.leader:
self._set_up_rule_memoization(node, result_type)
self.print("{")
if is_loop:
self._handle_loop_rule_body(node, rhs)
else:
self._handle_default_rule_body(node, rhs, result_type)
self.print("}")
def visit_NamedItem(self, node: NamedItem, names: List[str]) -> None:
name, call = self.callmakervisitor.visit(node)
if not name:
self.print(call)
else:
name = dedupe(name, names)
self.print(f"({name} = {call})")
def visit_Rhs(
self, node: Rhs, is_loop: bool, is_gather: bool, rulename: Optional[str]
) -> None:
if is_loop:
assert len(node.alts) == 1
for alt in node.alts:
self.visit(alt, is_loop=is_loop, is_gather=is_gather, rulename=rulename)
def join_conditions(self, keyword: str, node: Any, names: List[str]) -> None:
self.print(f"{keyword} (")
with self.indent():
first = True
for item in node.items:
if first:
first = False
else:
self.print("&&")
self.visit(item, names=names)
self.print(")")
def emit_action(self, node: Alt, cleanup_code=None) -> None:
self.print(f"res = {node.action};")
self.print("if (res == NULL && PyErr_Occurred()) {")
with self.indent():
self.print("p->error_indicator = 1;")
if cleanup_code:
self.print(cleanup_code)
self.print("return NULL;")
self.print("}")
if self.debug:
self.print(
f'fprintf(stderr, "Hit with action [%d-%d]: %s\\n", mark, p->mark, "{node}");'
)
def emit_default_action(self, is_gather: bool, names: List[str], node: Alt) -> None:
if len(names) > 1:
if is_gather:
assert len(names) == 2
self.print(f"res = _PyPegen_seq_insert_in_front(p, {names[0]}, {names[1]});")
else:
if self.debug:
self.print(
f'fprintf(stderr, "Hit without action [%d:%d]: %s\\n", mark, p->mark, "{node}");'
)
self.print(f"res = _PyPegen_dummy_name(p, {', '.join(names)});")
else:
if self.debug:
self.print(
f'fprintf(stderr, "Hit with default action [%d:%d]: %s\\n", mark, p->mark, "{node}");'
)
self.print(f"res = {names[0]};")
def emit_dummy_action(self) -> None:
self.print(f"res = _PyPegen_dummy_name(p);")
def handle_alt_normal(self, node: Alt, is_gather: bool, names: List[str]) -> None:
self.join_conditions(keyword="if", node=node, names=names)
self.print("{")
# We have parsed successfully all the conditions for the option.
with self.indent():
# Prepare to emmit the rule action and do so
if node.action and "EXTRA" in node.action:
self._set_up_token_end_metadata_extraction()
if self.skip_actions:
self.emit_dummy_action()
elif node.action:
self.emit_action(node)
else:
self.emit_default_action(is_gather, names, node)
# As the current option has parsed correctly, do not continue with the rest.
self.print(f"goto done;")
self.print("}")
def handle_alt_loop(
self, node: Alt, is_gather: bool, rulename: Optional[str], names: List[str]
) -> None:
# Condition of the main body of the alternative
self.join_conditions(keyword="while", node=node, names=names)
self.print("{")
# We have parsed successfully one item!
with self.indent():
# Prepare to emit the rule action and do so
if node.action and "EXTRA" in node.action:
self._set_up_token_end_metadata_extraction()
if self.skip_actions:
self.emit_dummy_action()
elif node.action:
self.emit_action(node, cleanup_code="PyMem_Free(children);")
else:
self.emit_default_action(is_gather, names, node)
# Add the result of rule to the temporary buffer of children. This buffer
# will populate later an asdl_seq with all elements to return.
self.print("if (n == children_capacity) {")
with self.indent():
self.print("children_capacity *= 2;")
self.print("children = PyMem_Realloc(children, children_capacity*sizeof(void *));")
self.out_of_memory_return(f"!children", "NULL", message=f"realloc {rulename}")
self.print("}")
self.print(f"children[n++] = res;")
self.print("mark = p->mark;")
self.print("}")
def visit_Alt(
self, node: Alt, is_loop: bool, is_gather: bool, rulename: Optional[str]
) -> None:
self.print(f"{{ // {node}")
with self.indent():
# Prepare variable declarations for the alternative
vars = self.collect_vars(node)
for v, var_type in sorted(item for item in vars.items() if item[0] is not None):
if not var_type:
var_type = "void *"
else:
var_type += " "
if v == "cut_var":
v += " = 0" # cut_var must be initialized
self.print(f"{var_type}{v};")
if v == "opt_var":
self.print("UNUSED(opt_var); // Silence compiler warnings")
names: List[str] = []
if is_loop:
self.handle_alt_loop(node, is_gather, rulename, names)
else:
self.handle_alt_normal(node, is_gather, names)
self.print("p->mark = mark;")
if "cut_var" in names:
self.print("if (cut_var) return NULL;")
self.print("}")
def collect_vars(self, node: Alt) -> Dict[str, Optional[str]]:
names: List[str] = []
types = {}
for item in node.items:
name, type = self.add_var(item, names)
types[name] = type
return types
def add_var(self, node: NamedItem, names: List[str]) -> Tuple[str, Optional[str]]:
name: str
call: str
name, call = self.callmakervisitor.visit(node.item)
type = None
if not name:
return name, type
if name.startswith("cut"):
return name, "int"
if name.endswith("_var"):
rulename = name[:-4]
rule = self.rules.get(rulename)
if rule is not None:
if rule.is_loop() or rule.is_gather():
type = "asdl_seq *"
else:
type = rule.type
elif name.startswith("_loop") or name.startswith("_gather"):
type = "asdl_seq *"
elif name in ("name_var", "string_var", "number_var"):
type = "expr_ty"
if node.name:
name = node.name
name = dedupe(name, names)
return name, type

153
Tools/peg_generator/pegen/first_sets.py Executable file
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@ -0,0 +1,153 @@
#!/usr/bin/env python3.8
import argparse
import collections
import pprint
import sys
from typing import Optional, Set, Dict
from pegen.build import build_parser
from pegen.grammar import (
Alt,
Cut,
Gather,
Grammar,
GrammarVisitor,
Group,
Leaf,
Lookahead,
NamedItem,
NameLeaf,
NegativeLookahead,
Opt,
Repeat,
Repeat0,
Repeat1,
Rhs,
Rule,
StringLeaf,
PositiveLookahead,
)
argparser = argparse.ArgumentParser(
prog="calculate_first_sets", description="Calculate the first sets of a grammar",
)
argparser.add_argument("grammar_file", help="The grammar file")
class FirstSetCalculator(GrammarVisitor):
def __init__(self, rules: Dict[str, Rule]) -> None:
self.rules = rules
for rule in rules.values():
rule.nullable_visit(rules)
self.first_sets: Dict[str, Set[str]] = dict()
self.in_process: Set[str] = set()
def calculate(self) -> Dict[str, Set[str]]:
for name, rule in self.rules.items():
self.visit(rule)
return self.first_sets
def visit_Alt(self, item: Alt) -> Set[str]:
result: Set[str] = set()
to_remove: Set[str] = set()
for other in item.items:
new_terminals = self.visit(other)
if isinstance(other.item, NegativeLookahead):
to_remove |= new_terminals
result |= new_terminals
if to_remove:
result -= to_remove
# If the set of new terminals can start with the empty string,
# it means that the item is completelly nullable and we should
# also considering at least the next item in case the current
# one fails to parse.
if "" in new_terminals:
continue
if not isinstance(other.item, (Opt, NegativeLookahead, Repeat0)):
break
# Do not allow the empty string to propagate.
result.discard("")
return result
def visit_Cut(self, item: Cut) -> Set[str]:
return set()
def visit_Group(self, item: Group) -> Set[str]:
return self.visit(item.rhs)
def visit_PositiveLookahead(self, item: Lookahead) -> Set[str]:
return self.visit(item.node)
def visit_NegativeLookahead(self, item: NegativeLookahead) -> Set[str]:
return self.visit(item.node)
def visit_NamedItem(self, item: NamedItem) -> Set[str]:
return self.visit(item.item)
def visit_Opt(self, item: Opt) -> Set[str]:
return self.visit(item.node)
def visit_Gather(self, item: Gather) -> Set[str]:
return self.visit(item.node)
def visit_Repeat0(self, item: Repeat0) -> Set[str]:
return self.visit(item.node)
def visit_Repeat1(self, item: Repeat1) -> Set[str]:
return self.visit(item.node)
def visit_NameLeaf(self, item: NameLeaf) -> Set[str]:
if item.value not in self.rules:
return {item.value}
if item.value not in self.first_sets:
self.first_sets[item.value] = self.visit(self.rules[item.value])
return self.first_sets[item.value]
elif item.value in self.in_process:
return set()
return self.first_sets[item.value]
def visit_StringLeaf(self, item: StringLeaf) -> Set[str]:
return {item.value}
def visit_Rhs(self, item: Rhs) -> Set[str]:
result: Set[str] = set()
for alt in item.alts:
result |= self.visit(alt)
return result
def visit_Rule(self, item: Rule) -> Set[str]:
if item.name in self.in_process:
return set()
elif item.name not in self.first_sets:
self.in_process.add(item.name)
terminals = self.visit(item.rhs)
if item.nullable:
terminals.add("")
self.first_sets[item.name] = terminals
self.in_process.remove(item.name)
return self.first_sets[item.name]
def main() -> None:
args = argparser.parse_args()
try:
grammar, parser, tokenizer = build_parser(args.grammar_file)
except Exception as err:
print("ERROR: Failed to parse grammar file", file=sys.stderr)
sys.exit(1)
firs_sets = FirstSetCalculator(grammar.rules).calculate()
pprint.pprint(firs_sets)
if __name__ == "__main__":
main()

470
Tools/peg_generator/pegen/grammar.py Normal file
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from __future__ import annotations
from abc import abstractmethod
from typing import (
AbstractSet,
Any,
Callable,
Dict,
Iterable,
Iterator,
List,
Optional,
Set,
Tuple,
TYPE_CHECKING,
TypeVar,
Union,
)
from pegen.parser import memoize, Parser
if TYPE_CHECKING:
from pegen.parser_generator import ParserGenerator
class GrammarError(Exception):
pass
class GrammarVisitor:
def visit(self, node: Any, *args: Any, **kwargs: Any) -> Any:
"""Visit a node."""
method = "visit_" + node.__class__.__name__
visitor = getattr(self, method, self.generic_visit)
return visitor(node, *args, **kwargs)
def generic_visit(self, node: Iterable[Any], *args: Any, **kwargs: Any) -> None:
"""Called if no explicit visitor function exists for a node."""
for value in node:
if isinstance(value, list):
for item in value:
self.visit(item, *args, **kwargs)
else:
self.visit(value, *args, **kwargs)
class Grammar:
def __init__(self, rules: Iterable[Rule], metas: Iterable[Tuple[str, Optional[str]]]):
self.rules = {rule.name: rule for rule in rules}
self.metas = dict(metas)
def __str__(self) -> str:
return "\n".join(str(rule) for name, rule in self.rules.items())
def __repr__(self) -> str:
lines = ["Grammar("]
lines.append(" [")
for rule in self.rules.values():
lines.append(f" {repr(rule)},")
lines.append(" ],")
lines.append(" {repr(list(self.metas.items()))}")
lines.append(")")
return "\n".join(lines)
def __iter__(self) -> Iterator[Rule]:
yield from self.rules.values()
# Global flag whether we want actions in __str__() -- default off.
SIMPLE_STR = True
class Rule:
def __init__(self, name: str, type: Optional[str], rhs: Rhs, memo: Optional[object] = None):
self.name = name
self.type = type
self.rhs = rhs
self.memo = bool(memo)
self.visited = False
self.nullable = False
self.left_recursive = False
self.leader = False
def is_loop(self) -> bool:
return self.name.startswith("_loop")
def is_gather(self) -> bool:
return self.name.startswith("_gather")
def __str__(self) -> str:
if SIMPLE_STR or self.type is None:
res = f"{self.name}: {self.rhs}"
else:
res = f"{self.name}[{self.type}]: {self.rhs}"
if len(res) < 88:
return res
lines = [res.split(":")[0] + ":"]
lines += [f" | {alt}" for alt in self.rhs.alts]
return "\n".join(lines)
def __repr__(self) -> str:
return f"Rule({self.name!r}, {self.type!r}, {self.rhs!r})"
def __iter__(self) -> Iterator[Rhs]:
yield self.rhs
def nullable_visit(self, rules: Dict[str, Rule]) -> bool:
if self.visited:
# A left-recursive rule is considered non-nullable.
return False
self.visited = True
self.nullable = self.rhs.nullable_visit(rules)
return self.nullable
def initial_names(self) -> AbstractSet[str]:
return self.rhs.initial_names()
def flatten(self) -> Rhs:
# If it's a single parenthesized group, flatten it.
rhs = self.rhs
if (
not self.is_loop()
and len(rhs.alts) == 1
and len(rhs.alts[0].items) == 1
and isinstance(rhs.alts[0].items[0].item, Group)
):
rhs = rhs.alts[0].items[0].item.rhs
return rhs
def collect_todo(self, gen: ParserGenerator) -> None:
rhs = self.flatten()
rhs.collect_todo(gen)
class Leaf:
def __init__(self, value: str):
self.value = value
def __str__(self) -> str:
return self.value
def __iter__(self) -> Iterable[str]:
if False:
yield
@abstractmethod
def nullable_visit(self, rules: Dict[str, Rule]) -> bool:
raise NotImplementedError
@abstractmethod
def initial_names(self) -> AbstractSet[str]:
raise NotImplementedError
class NameLeaf(Leaf):
"""The value is the name."""
def __str__(self) -> str:
if self.value == "ENDMARKER":
return "$"
return super().__str__()
def __repr__(self) -> str:
return f"NameLeaf({self.value!r})"
def nullable_visit(self, rules: Dict[str, Rule]) -> bool:
if self.value in rules:
return rules[self.value].nullable_visit(rules)
# Token or unknown; never empty.
return False
def initial_names(self) -> AbstractSet[str]:
return {self.value}
class StringLeaf(Leaf):
"""The value is a string literal, including quotes."""
def __repr__(self) -> str:
return f"StringLeaf({self.value!r})"
def nullable_visit(self, rules: Dict[str, Rule]) -> bool:
# The string token '' is considered empty.
return not self.value
def initial_names(self) -> AbstractSet[str]:
return set()
class Rhs:
def __init__(self, alts: List[Alt]):
self.alts = alts
self.memo: Optional[Tuple[Optional[str], str]] = None
def __str__(self) -> str:
return " | ".join(str(alt) for alt in self.alts)
def __repr__(self) -> str:
return f"Rhs({self.alts!r})"
def __iter__(self) -> Iterator[List[Alt]]:
yield self.alts
def nullable_visit(self, rules: Dict[str, Rule]) -> bool:
for alt in self.alts:
if alt.nullable_visit(rules):
return True
return False
def initial_names(self) -> AbstractSet[str]:
names: Set[str] = set()
for alt in self.alts:
names |= alt.initial_names()
return names
def collect_todo(self, gen: ParserGenerator) -> None:
for alt in self.alts:
alt.collect_todo(gen)
class Alt:
def __init__(self, items: List[NamedItem], *, icut: int = -1, action: Optional[str] = None):
self.items = items
self.icut = icut
self.action = action
def __str__(self) -> str:
core = " ".join(str(item) for item in self.items)
if not SIMPLE_STR and self.action:
return f"{core} {{ {self.action} }}"
else:
return core
def __repr__(self) -> str:
args = [repr(self.items)]
if self.icut >= 0:
args.append(f"icut={self.icut}")
if self.action:
args.append(f"action={self.action!r}")
return f"Alt({', '.join(args)})"
def __iter__(self) -> Iterator[List[NamedItem]]:
yield self.items
def nullable_visit(self, rules: Dict[str, Rule]) -> bool:
for item in self.items:
if not item.nullable_visit(rules):
return False
return True
def initial_names(self) -> AbstractSet[str]:
names: Set[str] = set()
for item in self.items:
names |= item.initial_names()
if not item.nullable:
break
return names
def collect_todo(self, gen: ParserGenerator) -> None:
for item in self.items:
item.collect_todo(gen)
class NamedItem:
def __init__(self, name: Optional[str], item: Item):
self.name = name
self.item = item
self.nullable = False
def __str__(self) -> str:
if not SIMPLE_STR and self.name:
return f"{self.name}={self.item}"
else:
return str(self.item)
def __repr__(self) -> str:
return f"NamedItem({self.name!r}, {self.item!r})"
def __iter__(self) -> Iterator[Item]:
yield self.item
def nullable_visit(self, rules: Dict[str, Rule]) -> bool:
self.nullable = self.item.nullable_visit(rules)
return self.nullable
def initial_names(self) -> AbstractSet[str]:
return self.item.initial_names()
def collect_todo(self, gen: ParserGenerator) -> None:
gen.callmakervisitor.visit(self.item)
class Lookahead:
def __init__(self, node: Plain, sign: str):
self.node = node
self.sign = sign
def __str__(self) -> str:
return f"{self.sign}{self.node}"
def __iter__(self) -> Iterator[Plain]:
yield self.node
def nullable_visit(self, rules: Dict[str, Rule]) -> bool:
return True
def initial_names(self) -> AbstractSet[str]:
return set()
class PositiveLookahead(Lookahead):
def __init__(self, node: Plain):
super().__init__(node, "&")
def __repr__(self) -> str:
return f"PositiveLookahead({self.node!r})"
class NegativeLookahead(Lookahead):
def __init__(self, node: Plain):
super().__init__(node, "!")
def __repr__(self) -> str:
return f"NegativeLookahead({self.node!r})"
class Opt:
def __init__(self, node: Item):
self.node = node
def __str__(self) -> str:
s = str(self.node)
# TODO: Decide whether to use [X] or X? based on type of X
if " " in s:
return f"[{s}]"
else:
return f"{s}?"
def __repr__(self) -> str:
return f"Opt({self.node!r})"
def __iter__(self) -> Iterator[Item]:
yield self.node
def nullable_visit(self, rules: Dict[str, Rule]) -> bool:
return True
def initial_names(self) -> AbstractSet[str]:
return self.node.initial_names()
class Repeat:
"""Shared base class for x* and x+."""
def __init__(self, node: Plain):
self.node = node
self.memo: Optional[Tuple[Optional[str], str]] = None
@abstractmethod
def nullable_visit(self, rules: Dict[str, Rule]) -> bool:
raise NotImplementedError
def __iter__(self) -> Iterator[Plain]:
yield self.node
def initial_names(self) -> AbstractSet[str]:
return self.node.initial_names()
class Repeat0(Repeat):
def __str__(self) -> str:
s = str(self.node)
# TODO: Decide whether to use (X)* or X* based on type of X
if " " in s:
return f"({s})*"
else:
return f"{s}*"
def __repr__(self) -> str:
return f"Repeat0({self.node!r})"
def nullable_visit(self, rules: Dict[str, Rule]) -> bool:
return True
class Repeat1(Repeat):
def __str__(self) -> str:
s = str(self.node)
# TODO: Decide whether to use (X)+ or X+ based on type of X
if " " in s:
return f"({s})+"
else:
return f"{s}+"
def __repr__(self) -> str:
return f"Repeat1({self.node!r})"
def nullable_visit(self, rules: Dict[str, Rule]) -> bool:
return False
class Gather(Repeat):
def __init__(self, separator: Plain, node: Plain):
self.separator = separator
self.node = node
def __str__(self) -> str:
return f"{self.separator!s}.{self.node!s}+"
def __repr__(self) -> str:
return f"Gather({self.separator!r}, {self.node!r})"
def nullable_visit(self, rules: Dict[str, Rule]) -> bool:
return False
class Group:
def __init__(self, rhs: Rhs):
self.rhs = rhs
def __str__(self) -> str:
return f"({self.rhs})"
def __repr__(self) -> str:
return f"Group({self.rhs!r})"
def __iter__(self) -> Iterator[Rhs]:
yield self.rhs
def nullable_visit(self, rules: Dict[str, Rule]) -> bool:
return self.rhs.nullable_visit(rules)
def initial_names(self) -> AbstractSet[str]:
return self.rhs.initial_names()
class Cut:
def __init__(self) -> None:
pass
def __repr__(self) -> str:
return f"Cut()"
def __str__(self) -> str:
return f"~"
def __iter__(self) -> Iterator[Tuple[str, str]]:
if False:
yield
def __eq__(self, other: object) -> bool:
if not isinstance(other, Cut):
return NotImplemented
return True
def nullable_visit(self, rules: Dict[str, Rule]) -> bool:
return True
def initial_names(self) -> AbstractSet[str]:
return set()
Plain = Union[Leaf, Group]
Item = Union[Plain, Opt, Repeat, Lookahead, Rhs, Cut]
RuleName = Tuple[str, str]
MetaTuple = Tuple[str, Optional[str]]
MetaList = List[MetaTuple]
RuleList = List[Rule]
NamedItemList = List[NamedItem]
LookaheadOrCut = Union[Lookahead, Cut]

677
Tools/peg_generator/pegen/grammar_parser.py Normal file
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#!/usr/bin/env python3.8
# @generated by pegen from pegen/metagrammar.gram
import ast
import sys
import tokenize
from typing import Any, Optional
from pegen.parser import memoize, memoize_left_rec, logger, Parser
from ast import literal_eval
from pegen.grammar import (
Alt,
Cut,
Gather,
Group,
Item,
Lookahead,
LookaheadOrCut,
MetaTuple,
MetaList,
NameLeaf,
NamedItem,
NamedItemList,
NegativeLookahead,
Opt,
Plain,
PositiveLookahead,
Repeat0,
Repeat1,
Rhs,
Rule,
RuleList,
RuleName,
Grammar,
StringLeaf,
)
class GeneratedParser(Parser):
@memoize
def start(self) -> Optional[Grammar]:
# start: grammar $
mark = self.mark()
cut = False
if (
(grammar := self.grammar())
and
(endmarker := self.expect('ENDMARKER'))
):
return grammar
self.reset(mark)
if cut: return None
return None
@memoize
def grammar(self) -> Optional[Grammar]:
# grammar: metas rules | rules
mark = self.mark()
cut = False
if (
(metas := self.metas())
and
(rules := self.rules())
):
return Grammar ( rules , metas )
self.reset(mark)
if cut: return None
cut = False
if (
(rules := self.rules())
):
return Grammar ( rules , [ ] )
self.reset(mark)
if cut: return None
return None
@memoize
def metas(self) -> Optional[MetaList]:
# metas: meta metas | meta
mark = self.mark()
cut = False
if (
(meta := self.meta())
and
(metas := self.metas())
):
return [ meta ] + metas
self.reset(mark)
if cut: return None
cut = False
if (
(meta := self.meta())
):
return [ meta ]
self.reset(mark)
if cut: return None
return None
@memoize
def meta(self) -> Optional[MetaTuple]:
# meta: "@" NAME NEWLINE | "@" NAME NAME NEWLINE | "@" NAME STRING NEWLINE
mark = self.mark()
cut = False
if (
(literal := self.expect("@"))
and
(name := self.name())
and
(newline := self.expect('NEWLINE'))
):
return ( name . string , None )
self.reset(mark)
if cut: return None
cut = False
if (
(literal := self.expect("@"))
and
(a := self.name())
and
(b := self.name())
and
(newline := self.expect('NEWLINE'))
):
return ( a . string , b . string )
self.reset(mark)
if cut: return None
cut = False
if (
(literal := self.expect("@"))
and
(name := self.name())
and
(string := self.string())
and
(newline := self.expect('NEWLINE'))
):
return ( name . string , literal_eval ( string . string ) )
self.reset(mark)
if cut: return None
return None
@memoize
def rules(self) -> Optional[RuleList]:
# rules: rule rules | rule
mark = self.mark()
cut = False
if (
(rule := self.rule())
and
(rules := self.rules())
):
return [ rule ] + rules
self.reset(mark)
if cut: return None
cut = False
if (
(rule := self.rule())
):
return [ rule ]
self.reset(mark)
if cut: return None
return None
@memoize
def rule(self) -> Optional[Rule]:
# rule: rulename memoflag? ":" alts NEWLINE INDENT more_alts DEDENT | rulename memoflag? ":" NEWLINE INDENT more_alts DEDENT | rulename memoflag? ":" alts NEWLINE
mark = self.mark()
cut = False
if (
(rulename := self.rulename())
and
(opt := self.memoflag(),)
and
(literal := self.expect(":"))
and
(alts := self.alts())
and
(newline := self.expect('NEWLINE'))
and
(indent := self.expect('INDENT'))
and
(more_alts := self.more_alts())
and
(dedent := self.expect('DEDENT'))
):
return Rule ( rulename [ 0 ] , rulename [ 1 ] , Rhs ( alts . alts + more_alts . alts ) , memo = opt )
self.reset(mark)
if cut: return None
cut = False
if (
(rulename := self.rulename())
and
(opt := self.memoflag(),)
and
(literal := self.expect(":"))
and
(newline := self.expect('NEWLINE'))
and
(indent := self.expect('INDENT'))
and
(more_alts := self.more_alts())
and
(dedent := self.expect('DEDENT'))
):
return Rule ( rulename [ 0 ] , rulename [ 1 ] , more_alts , memo = opt )
self.reset(mark)
if cut: return None
cut = False
if (
(rulename := self.rulename())
and
(opt := self.memoflag(),)
and
(literal := self.expect(":"))
and
(alts := self.alts())
and
(newline := self.expect('NEWLINE'))
):
return Rule ( rulename [ 0 ] , rulename [ 1 ] , alts , memo = opt )
self.reset(mark)
if cut: return None
return None
@memoize
def rulename(self) -> Optional[RuleName]:
# rulename: NAME '[' NAME '*' ']' | NAME '[' NAME ']' | NAME
mark = self.mark()
cut = False
if (
(name := self.name())
and
(literal := self.expect('['))
and
(type := self.name())
and
(literal_1 := self.expect('*'))
and
(literal_2 := self.expect(']'))
):
return ( name . string , type . string + "*" )
self.reset(mark)
if cut: return None
cut = False
if (
(name := self.name())
and
(literal := self.expect('['))
and
(type := self.name())
and
(literal_1 := self.expect(']'))
):
return ( name . string , type . string )
self.reset(mark)
if cut: return None
cut = False
if (
(name := self.name())
):
return ( name . string , None )
self.reset(mark)
if cut: return None
return None
@memoize
def memoflag(self) -> Optional[str]:
# memoflag: '(' 'memo' ')'
mark = self.mark()
cut = False
if (
(literal := self.expect('('))
and
(literal_1 := self.expect('memo'))
and
(literal_2 := self.expect(')'))
):
return "memo"
self.reset(mark)
if cut: return None
return None
@memoize
def alts(self) -> Optional[Rhs]:
# alts: alt "|" alts | alt
mark = self.mark()
cut = False
if (
(alt := self.alt())
and
(literal := self.expect("|"))
and
(alts := self.alts())
):
return Rhs ( [ alt ] + alts . alts )
self.reset(mark)
if cut: return None
cut = False
if (
(alt := self.alt())
):
return Rhs ( [ alt ] )
self.reset(mark)
if cut: return None
return None
@memoize
def more_alts(self) -> Optional[Rhs]:
# more_alts: "|" alts NEWLINE more_alts | "|" alts NEWLINE
mark = self.mark()
cut = False
if (
(literal := self.expect("|"))
and
(alts := self.alts())
and
(newline := self.expect('NEWLINE'))
and
(more_alts := self.more_alts())
):
return Rhs ( alts . alts + more_alts . alts )
self.reset(mark)
if cut: return None
cut = False
if (
(literal := self.expect("|"))
and
(alts := self.alts())
and
(newline := self.expect('NEWLINE'))
):
return Rhs ( alts . alts )
self.reset(mark)
if cut: return None
return None
@memoize
def alt(self) -> Optional[Alt]:
# alt: items '$' action | items '$' | items action | items
mark = self.mark()
cut = False
if (
(items := self.items())
and
(literal := self.expect('$'))
and
(action := self.action())
):
return Alt ( items + [ NamedItem ( None , NameLeaf ( 'ENDMARKER' ) ) ] , action = action )
self.reset(mark)
if cut: return None
cut = False
if (
(items := self.items())
and
(literal := self.expect('$'))
):
return Alt ( items + [ NamedItem ( None , NameLeaf ( 'ENDMARKER' ) ) ] , action = None )
self.reset(mark)
if cut: return None
cut = False
if (
(items := self.items())
and
(action := self.action())
):
return Alt ( items , action = action )
self.reset(mark)
if cut: return None
cut = False
if (
(items := self.items())
):
return Alt ( items , action = None )
self.reset(mark)
if cut: return None
return None
@memoize
def items(self) -> Optional[NamedItemList]:
# items: named_item items | named_item
mark = self.mark()
cut = False
if (
(named_item := self.named_item())
and
(items := self.items())
):
return [ named_item ] + items
self.reset(mark)
if cut: return None
cut = False
if (
(named_item := self.named_item())
):
return [ named_item ]
self.reset(mark)
if cut: return None
return None
@memoize
def named_item(self) -> Optional[NamedItem]:
# named_item: NAME '=' ~ item | item | lookahead
mark = self.mark()
cut = False
if (
(name := self.name())
and
(literal := self.expect('='))
and
(cut := True)
and
(item := self.item())
):
return NamedItem ( name . string , item )
self.reset(mark)
if cut: return None
cut = False
if (
(item := self.item())
):
return NamedItem ( None , item )
self.reset(mark)
if cut: return None
cut = False
if (
(it := self.lookahead())
):
return NamedItem ( None , it )
self.reset(mark)
if cut: return None
return None
@memoize
def lookahead(self) -> Optional[LookaheadOrCut]:
# lookahead: '&' ~ atom | '!' ~ atom | '~'
mark = self.mark()
cut = False
if (
(literal := self.expect('&'))
and
(cut := True)
and
(atom := self.atom())
):
return PositiveLookahead ( atom )
self.reset(mark)
if cut: return None
cut = False
if (
(literal := self.expect('!'))
and
(cut := True)
and
(atom := self.atom())
):
return NegativeLookahead ( atom )
self.reset(mark)
if cut: return None
cut = False
if (
(literal := self.expect('~'))
):
return Cut ( )
self.reset(mark)
if cut: return None
return None
@memoize
def item(self) -> Optional[Item]:
# item: '[' ~ alts ']' | atom '?' | atom '*' | atom '+' | atom '.' atom '+' | atom
mark = self.mark()
cut = False
if (
(literal := self.expect('['))
and
(cut := True)
and
(alts := self.alts())
and
(literal_1 := self.expect(']'))
):
return Opt ( alts )
self.reset(mark)
if cut: return None
cut = False
if (
(atom := self.atom())
and
(literal := self.expect('?'))
):
return Opt ( atom )
self.reset(mark)
if cut: return None
cut = False
if (
(atom := self.atom())
and
(literal := self.expect('*'))
):
return Repeat0 ( atom )
self.reset(mark)
if cut: return None
cut = False
if (
(atom := self.atom())
and
(literal := self.expect('+'))
):
return Repeat1 ( atom )
self.reset(mark)
if cut: return None
cut = False
if (
(sep := self.atom())
and
(literal := self.expect('.'))
and
(node := self.atom())
and
(literal_1 := self.expect('+'))
):
return Gather ( sep , node )
self.reset(mark)
if cut: return None
cut = False
if (
(atom := self.atom())
):
return atom
self.reset(mark)
if cut: return None
return None
@memoize
def atom(self) -> Optional[Plain]:
# atom: '(' ~ alts ')' | NAME | STRING
mark = self.mark()
cut = False
if (
(literal := self.expect('('))
and
(cut := True)
and
(alts := self.alts())
and
(literal_1 := self.expect(')'))
):
return Group ( alts )
self.reset(mark)
if cut: return None
cut = False
if (
(name := self.name())
):
return NameLeaf ( name . string )
self.reset(mark)
if cut: return None
cut = False
if (
(string := self.string())
):
return StringLeaf ( string . string )
self.reset(mark)
if cut: return None
return None
@memoize
def action(self) -> Optional[str]:
# action: "{" ~ target_atoms "}"
mark = self.mark()
cut = False
if (
(literal := self.expect("{"))
and
(cut := True)
and
(target_atoms := self.target_atoms())
and
(literal_1 := self.expect("}"))
):
return target_atoms
self.reset(mark)
if cut: return None
return None
@memoize
def target_atoms(self) -> Optional[str]:
# target_atoms: target_atom target_atoms | target_atom
mark = self.mark()
cut = False
if (
(target_atom := self.target_atom())
and
(target_atoms := self.target_atoms())
):
return target_atom + " " + target_atoms
self.reset(mark)
if cut: return None
cut = False
if (
(target_atom := self.target_atom())
):
return target_atom
self.reset(mark)
if cut: return None
return None
@memoize
def target_atom(self) -> Optional[str]:
# target_atom: "{" ~ target_atoms "}" | NAME | NUMBER | STRING | "?" | ":" | !"}" OP
mark = self.mark()
cut = False
if (
(literal := self.expect("{"))
and
(cut := True)
and
(target_atoms := self.target_atoms())
and
(literal_1 := self.expect("}"))
):
return "{" + target_atoms + "}"
self.reset(mark)
if cut: return None
cut = False
if (
(name := self.name())
):
return name . string
self.reset(mark)
if cut: return None
cut = False
if (
(number := self.number())
):
return number . string
self.reset(mark)
if cut: return None
cut = False
if (
(string := self.string())
):
return string . string
self.reset(mark)
if cut: return None
cut = False
if (
(literal := self.expect("?"))
):
return "?"
self.reset(mark)
if cut: return None
cut = False
if (
(literal := self.expect(":"))
):
return ":"
self.reset(mark)
if cut: return None
cut = False
if (
self.negative_lookahead(self.expect, "}")
and
(op := self.op())
):
return op . string
self.reset(mark)
if cut: return None
return None
if __name__ == '__main__':
from pegen.parser import simple_parser_main
simple_parser_main(GeneratedParser)

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import argparse
import sys
from typing import Any, Iterator, Iterable, Callable
from pegen.build import build_parser
from pegen.grammar import Grammar, Rule
argparser = argparse.ArgumentParser(
prog="pegen", description="Pretty print the AST for a given PEG grammar"
)
argparser.add_argument("filename", help="Grammar description")
class ASTGrammarPrinter:
def children(self, node: Rule) -> Iterator[Any]:
for value in node:
if isinstance(value, list):
yield from value
else:
yield value
def name(self, node: Rule) -> str:
if not list(self.children(node)):
return repr(node)
return node.__class__.__name__
def print_grammar_ast(self, grammar: Grammar, printer: Callable[..., None] = print) -> None:
for rule in grammar.rules.values():
printer(self.print_nodes_recursively(rule))
def print_nodes_recursively(self, node: Rule, prefix: str = "", istail: bool = True) -> str:
children = list(self.children(node))
value = self.name(node)
line = prefix + ("└──" if istail else "├──") + value + "\n"
sufix = " " if istail else "│ "
if not children:
return line
*children, last = children
for child in children:
line += self.print_nodes_recursively(child, prefix + sufix, False)
line += self.print_nodes_recursively(last, prefix + sufix, True)
return line
def main() -> None:
args = argparser.parse_args()
try:
grammar, parser, tokenizer = build_parser(args.filename)
except Exception as err:
print("ERROR: Failed to parse grammar file", file=sys.stderr)
sys.exit(1)
visitor = ASTGrammarPrinter()
visitor.print_grammar_ast(grammar)
if __name__ == "__main__":
main()

123
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@subheader """\
from ast import literal_eval
from pegen.grammar import (
Alt,
Cut,
Gather,
Group,
Item,
Lookahead,
LookaheadOrCut,
MetaTuple,
MetaList,
NameLeaf,
NamedItem,
NamedItemList,
NegativeLookahead,
Opt,
Plain,
PositiveLookahead,
Repeat0,
Repeat1,
Rhs,
Rule,
RuleList,
RuleName,
Grammar,
StringLeaf,
)
"""
start[Grammar]: grammar ENDMARKER { grammar }
grammar[Grammar]:
| metas rules { Grammar(rules, metas) }
| rules { Grammar(rules, []) }
metas[MetaList]:
| meta metas { [meta] + metas }
| meta { [meta] }
meta[MetaTuple]:
| "@" NAME NEWLINE { (name.string, None) }
| "@" a=NAME b=NAME NEWLINE { (a.string, b.string) }
| "@" NAME STRING NEWLINE { (name.string, literal_eval(string.string)) }
rules[RuleList]:
| rule rules { [rule] + rules }
| rule { [rule] }
rule[Rule]:
| rulename memoflag? ":" alts NEWLINE INDENT more_alts DEDENT {
Rule(rulename[0], rulename[1], Rhs(alts.alts + more_alts.alts), memo=opt) }
| rulename memoflag? ":" NEWLINE INDENT more_alts DEDENT {
Rule(rulename[0], rulename[1], more_alts, memo=opt) }
| rulename memoflag? ":" alts NEWLINE { Rule(rulename[0], rulename[1], alts, memo=opt) }
rulename[RuleName]:
| NAME '[' type=NAME '*' ']' { (name.string, type.string+"*") }
| NAME '[' type=NAME ']' { (name.string, type.string) }
| NAME { (name.string, None) }
# In the future this may return something more complicated
memoflag[str]:
| '(' 'memo' ')' { "memo" }
alts[Rhs]:
| alt "|" alts { Rhs([alt] + alts.alts)}
| alt { Rhs([alt]) }
more_alts[Rhs]:
| "|" alts NEWLINE more_alts { Rhs(alts.alts + more_alts.alts) }
| "|" alts NEWLINE { Rhs(alts.alts) }
alt[Alt]:
| items '$' action { Alt(items + [NamedItem(None, NameLeaf('ENDMARKER'))], action=action) }
| items '$' { Alt(items + [NamedItem(None, NameLeaf('ENDMARKER'))], action=None) }
| items action { Alt(items, action=action) }
| items { Alt(items, action=None) }
items[NamedItemList]:
| named_item items { [named_item] + items }
| named_item { [named_item] }
named_item[NamedItem]:
| NAME '=' ~ item {NamedItem(name.string, item)}
| item {NamedItem(None, item)}
| it=lookahead {NamedItem(None, it)}
lookahead[LookaheadOrCut]:
| '&' ~ atom {PositiveLookahead(atom)}
| '!' ~ atom {NegativeLookahead(atom)}
| '~' {Cut()}
item[Item]:
| '[' ~ alts ']' {Opt(alts)}
| atom '?' {Opt(atom)}
| atom '*' {Repeat0(atom)}
| atom '+' {Repeat1(atom)}
| sep=atom '.' node=atom '+' {Gather(sep, node)}
| atom {atom}
atom[Plain]:
| '(' ~ alts ')' {Group(alts)}
| NAME {NameLeaf(name.string) }
| STRING {StringLeaf(string.string)}
# Mini-grammar for the actions
action[str]: "{" ~ target_atoms "}" { target_atoms }
target_atoms[str]:
| target_atom target_atoms { target_atom + " " + target_atoms }
| target_atom { target_atom }
target_atom[str]:
| "{" ~ target_atoms "}" { "{" + target_atoms + "}" }
| NAME { name.string }
| NUMBER { number.string }
| STRING { string.string }
| "?" { "?" }
| ":" { ":" }
| !"}" OP { op.string }

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import argparse
import sys
import time
import token
import tokenize
import traceback
from abc import abstractmethod
from typing import Any, Callable, cast, Dict, Optional, Tuple, Type, TypeVar
from pegen.tokenizer import exact_token_types
from pegen.tokenizer import Mark
from pegen.tokenizer import Tokenizer
T = TypeVar("T")
P = TypeVar("P", bound="Parser")
F = TypeVar("F", bound=Callable[..., Any])
def logger(method: F) -> F:
"""For non-memoized functions that we want to be logged.
(In practice this is only non-leader left-recursive functions.)
"""
method_name = method.__name__
def logger_wrapper(self: P, *args: object) -> T:
if not self._verbose:
return method(self, *args)
argsr = ",".join(repr(arg) for arg in args)
fill = " " * self._level
print(f"{fill}{method_name}({argsr}) .... (looking at {self.showpeek()})")
self._level += 1
tree = method(self, *args)
self._level -= 1
print(f"{fill}... {method_name}({argsr}) --> {tree!s:.200}")
return tree
logger_wrapper.__wrapped__ = method # type: ignore
return cast(F, logger_wrapper)
def memoize(method: F) -> F:
"""Memoize a symbol method."""
method_name = method.__name__
def memoize_wrapper(self: P, *args: object) -> T:
mark = self.mark()
key = mark, method_name, args
# Fast path: cache hit, and not verbose.
if key in self._cache and not self._verbose:
tree, endmark = self._cache[key]
self.reset(endmark)
return tree
# Slow path: no cache hit, or verbose.
verbose = self._verbose
argsr = ",".join(repr(arg) for arg in args)
fill = " " * self._level
if key not in self._cache:
if verbose:
print(f"{fill}{method_name}({argsr}) ... (looking at {self.showpeek()})")
self._level += 1
tree = method(self, *args)
self._level -= 1
if verbose:
print(f"{fill}... {method_name}({argsr}) -> {tree!s:.200}")
endmark = self.mark()
self._cache[key] = tree, endmark
else:
tree, endmark = self._cache[key]
if verbose:
print(f"{fill}{method_name}({argsr}) -> {tree!s:.200}")
self.reset(endmark)
return tree
memoize_wrapper.__wrapped__ = method # type: ignore
return cast(F, memoize_wrapper)
def memoize_left_rec(method: Callable[[P], Optional[T]]) -> Callable[[P], Optional[T]]:
"""Memoize a left-recursive symbol method."""
method_name = method.__name__
def memoize_left_rec_wrapper(self: P) -> Optional[T]:
mark = self.mark()
key = mark, method_name, ()
# Fast path: cache hit, and not verbose.
if key in self._cache and not self._verbose:
tree, endmark = self._cache[key]
self.reset(endmark)
return tree
# Slow path: no cache hit, or verbose.
verbose = self._verbose
fill = " " * self._level
if key not in self._cache:
if verbose:
print(f"{fill}{method_name} ... (looking at {self.showpeek()})")
self._level += 1
# For left-recursive rules we manipulate the cache and
# loop until the rule shows no progress, then pick the
# previous result. For an explanation why this works, see
# https://github.com/PhilippeSigaud/Pegged/wiki/Left-Recursion
# (But we use the memoization cache instead of a static
# variable; perhaps this is similar to a paper by Warth et al.
# (http://web.cs.ucla.edu/~todd/research/pub.php?id=pepm08).
# Prime the cache with a failure.
self._cache[key] = None, mark
lastresult, lastmark = None, mark
depth = 0
if verbose:
print(f"{fill}Recursive {method_name} at {mark} depth {depth}")
while True:
self.reset(mark)
result = method(self)
endmark = self.mark()
depth += 1
if verbose:
print(
f"{fill}Recursive {method_name} at {mark} depth {depth}: {result!s:.200} to {endmark}"
)
if not result:
if verbose:
print(f"{fill}Fail with {lastresult!s:.200} to {lastmark}")
break
if endmark <= lastmark:
if verbose:
print(f"{fill}Bailing with {lastresult!s:.200} to {lastmark}")
break
self._cache[key] = lastresult, lastmark = result, endmark
self.reset(lastmark)
tree = lastresult
self._level -= 1
if verbose:
print(f"{fill}{method_name}() -> {tree!s:.200} [cached]")
if tree:
endmark = self.mark()
else:
endmark = mark
self.reset(endmark)
self._cache[key] = tree, endmark
else:
tree, endmark = self._cache[key]
if verbose:
print(f"{fill}{method_name}() -> {tree!s:.200} [fresh]")
if tree:
self.reset(endmark)
return tree
memoize_left_rec_wrapper.__wrapped__ = method # type: ignore
return memoize_left_rec_wrapper
class Parser:
"""Parsing base class."""
def __init__(self, tokenizer: Tokenizer, *, verbose: bool = False):
self._tokenizer = tokenizer
self._verbose = verbose
self._level = 0
self._cache: Dict[Tuple[Mark, str, Tuple[Any, ...]], Tuple[Any, Mark]] = {}
# Pass through common tokenizer methods.
# TODO: Rename to _mark and _reset.
self.mark = self._tokenizer.mark
self.reset = self._tokenizer.reset
@abstractmethod
def start(self) -> Any:
pass
def showpeek(self) -> str:
tok = self._tokenizer.peek()
return f"{tok.start[0]}.{tok.start[1]}: {token.tok_name[tok.type]}:{tok.string!r}"
@memoize
def name(self) -> Optional[tokenize.TokenInfo]:
tok = self._tokenizer.peek()
if tok.type == token.NAME:
return self._tokenizer.getnext()
return None
@memoize
def number(self) -> Optional[tokenize.TokenInfo]:
tok = self._tokenizer.peek()
if tok.type == token.NUMBER:
return self._tokenizer.getnext()
return None
@memoize
def string(self) -> Optional[tokenize.TokenInfo]:
tok = self._tokenizer.peek()
if tok.type == token.STRING:
return self._tokenizer.getnext()
return None
@memoize
def op(self) -> Optional[tokenize.TokenInfo]:
tok = self._tokenizer.peek()
if tok.type == token.OP:
return self._tokenizer.getnext()
return None
@memoize
def expect(self, type: str) -> Optional[tokenize.TokenInfo]:
tok = self._tokenizer.peek()
if tok.string == type:
return self._tokenizer.getnext()
if type in exact_token_types:
if tok.type == exact_token_types[type]:
return self._tokenizer.getnext()
if type in token.__dict__:
if tok.type == token.__dict__[type]:
return self._tokenizer.getnext()
if tok.type == token.OP and tok.string == type:
return self._tokenizer.getnext()
return None
def positive_lookahead(self, func: Callable[..., T], *args: object) -> T:
mark = self.mark()
ok = func(*args)
self.reset(mark)
return ok
def negative_lookahead(self, func: Callable[..., object], *args: object) -> bool:
mark = self.mark()
ok = func(*args)
self.reset(mark)
return not ok
def make_syntax_error(self, filename: str = "<unknown>") -> SyntaxError:
tok = self._tokenizer.diagnose()
return SyntaxError(
"pegen parse failure", (filename, tok.start[0], 1 + tok.start[1], tok.line)
)
def simple_parser_main(parser_class: Type[Parser]) -> None:
argparser = argparse.ArgumentParser()
argparser.add_argument(
"-v",
"--verbose",
action="count",
default=0,
help="Print timing stats; repeat for more debug output",
)
argparser.add_argument(
"-q", "--quiet", action="store_true", help="Don't print the parsed program"
)
argparser.add_argument("filename", help="Input file ('-' to use stdin)")
args = argparser.parse_args()
verbose = args.verbose
verbose_tokenizer = verbose >= 3
verbose_parser = verbose == 2 or verbose >= 4
t0 = time.time()
filename = args.filename
if filename == "" or filename == "-":
filename = "<stdin>"
file = sys.stdin
else:
file = open(args.filename)
try:
tokengen = tokenize.generate_tokens(file.readline)
tokenizer = Tokenizer(tokengen, verbose=verbose_tokenizer)
parser = parser_class(tokenizer, verbose=verbose_parser)
tree = parser.start()
try:
if file.isatty():
endpos = 0
else:
endpos = file.tell()
except IOError:
endpos = 0
finally:
if file is not sys.stdin:
file.close()
t1 = time.time()
if not tree:
err = parser.make_syntax_error(filename)
traceback.print_exception(err.__class__, err, None)
sys.exit(1)
if not args.quiet:
print(tree)
if verbose:
dt = t1 - t0
diag = tokenizer.diagnose()
nlines = diag.end[0]
if diag.type == token.ENDMARKER:
nlines -= 1
print(f"Total time: {dt:.3f} sec; {nlines} lines", end="")
if endpos:
print(f" ({endpos} bytes)", end="")
if dt:
print(f"; {nlines / dt:.0f} lines/sec")
else:
print()
print("Caches sizes:")
print(f" token array : {len(tokenizer._tokens):10}")
print(f" cache : {len(parser._cache):10}")
## print_memstats()

188
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import contextlib
import token
from abc import abstractmethod
from typing import AbstractSet, Dict, IO, Iterator, List, Optional, Set, Text, Tuple
from pegen import sccutils
from pegen.grammar import (
Grammar,
Rule,
Rhs,
Alt,
NamedItem,
Plain,
NameLeaf,
StringLeaf,
Gather,
)
from pegen.grammar import GrammarError, GrammarVisitor
class RuleCheckingVisitor(GrammarVisitor):
def __init__(self, rules: Dict[str, Rule]):
self.rules = rules
def visit_NameLeaf(self, node: NameLeaf) -> None:
if node.value not in self.rules and node.value not in token.tok_name.values():
# TODO: Add line/col info to (leaf) nodes
raise GrammarError(f"Dangling reference to rule {node.value!r}")
class ParserGenerator:
callmakervisitor: GrammarVisitor
def __init__(self, grammar: Grammar, file: Optional[IO[Text]]):
self.grammar = grammar
self.rules = grammar.rules
if "trailer" not in grammar.metas and "start" not in self.rules:
raise GrammarError("Grammar without a trailer must have a 'start' rule")
checker = RuleCheckingVisitor(self.rules)
for rule in self.rules.values():
checker.visit(rule)
self.file = file
self.level = 0
compute_nullables(self.rules)
self.first_graph, self.first_sccs = compute_left_recursives(self.rules)
self.todo = self.rules.copy() # Rules to generate
self.counter = 0 # For name_rule()/name_loop()
self.keyword_counter = 499 # For keyword_type()
@abstractmethod
def generate(self, filename: str) -> None:
raise NotImplementedError
@contextlib.contextmanager
def indent(self) -> Iterator[None]:
self.level += 1
try:
yield
finally:
self.level -= 1
def print(self, *args: object) -> None:
if not args:
print(file=self.file)
else:
print(" " * self.level, end="", file=self.file)
print(*args, file=self.file)
def printblock(self, lines: str) -> None:
for line in lines.splitlines():
self.print(line)
def collect_todo(self) -> None:
done: Set[str] = set()
while True:
alltodo = list(self.todo)
todo = [i for i in alltodo if i not in done]
if not todo:
break
for rulename in todo:
self.todo[rulename].collect_todo(self)
done = set(alltodo)
def keyword_type(self) -> int:
self.keyword_counter += 1
return self.keyword_counter
def name_node(self, rhs: Rhs) -> str:
self.counter += 1
name = f"_tmp_{self.counter}" # TODO: Pick a nicer name.
self.todo[name] = Rule(name, None, rhs)
return name
def name_loop(self, node: Plain, is_repeat1: bool) -> str:
self.counter += 1
if is_repeat1:
prefix = "_loop1_"
else:
prefix = "_loop0_"
name = f"{prefix}{self.counter}" # TODO: It's ugly to signal via the name.
self.todo[name] = Rule(name, None, Rhs([Alt([NamedItem(None, node)])]))
return name
def name_gather(self, node: Gather) -> str:
self.counter += 1
name = f"_gather_{self.counter}"
self.counter += 1
extra_function_name = f"_loop0_{self.counter}"
extra_function_alt = Alt(
[NamedItem(None, node.separator), NamedItem("elem", node.node),], action="elem",
)
self.todo[extra_function_name] = Rule(
extra_function_name, None, Rhs([extra_function_alt]),
)
alt = Alt(
[NamedItem("elem", node.node), NamedItem("seq", NameLeaf(extra_function_name)),],
)
self.todo[name] = Rule(name, None, Rhs([alt]),)
return name
def dedupe(name: str, names: List[str]) -> str:
origname = name
counter = 0
while name in names:
counter += 1
name = f"{origname}_{counter}"
names.append(name)
return name
def compute_nullables(rules: Dict[str, Rule]) -> None:
"""Compute which rules in a grammar are nullable.
Thanks to TatSu (tatsu/leftrec.py) for inspiration.
"""
for rule in rules.values():
rule.nullable_visit(rules)
def compute_left_recursives(
rules: Dict[str, Rule]
) -> Tuple[Dict[str, AbstractSet[str]], List[AbstractSet[str]]]:
graph = make_first_graph(rules)
sccs = list(sccutils.strongly_connected_components(graph.keys(), graph))
for scc in sccs:
if len(scc) > 1:
for name in scc:
rules[name].left_recursive = True
# Try to find a leader such that all cycles go through it.
leaders = set(scc)
for start in scc:
for cycle in sccutils.find_cycles_in_scc(graph, scc, start):
## print("Cycle:", " -> ".join(cycle))
leaders -= scc - set(cycle)
if not leaders:
raise ValueError(
f"SCC {scc} has no leadership candidate (no element is included in all cycles)"
)
## print("Leaders:", leaders)
leader = min(leaders) # Pick an arbitrary leader from the candidates.
rules[leader].leader = True
else:
name = min(scc) # The only element.
if name in graph[name]:
rules[name].left_recursive = True
rules[name].leader = True
return graph, sccs
def make_first_graph(rules: Dict[str, Rule]) -> Dict[str, AbstractSet[str]]:
"""Compute the graph of left-invocations.
There's an edge from A to B if A may invoke B at its initial
position.
Note that this requires the nullable flags to have been computed.
"""
graph = {}
vertices: Set[str] = set()
for rulename, rhs in rules.items():
graph[rulename] = names = rhs.initial_names()
vertices |= names
for vertex in vertices:
graph.setdefault(vertex, set())
return graph

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from typing import Any, Dict, List, Optional, IO, Text, Tuple
from pegen.grammar import (
Cut,
GrammarVisitor,
NameLeaf,
StringLeaf,
Rhs,
NamedItem,
Lookahead,
PositiveLookahead,
NegativeLookahead,
Opt,
Repeat0,
Repeat1,
Gather,
Group,
Rule,
Alt,
)
from pegen import grammar
from pegen.parser_generator import dedupe, ParserGenerator
MODULE_PREFIX = """\
#!/usr/bin/env python3.8
# @generated by pegen from {filename}
import ast
import sys
import tokenize
from typing import Any, Optional
from pegen.parser import memoize, memoize_left_rec, logger, Parser
"""
MODULE_SUFFIX = """
if __name__ == '__main__':
from pegen.parser import simple_parser_main
simple_parser_main(GeneratedParser)
"""
class PythonCallMakerVisitor(GrammarVisitor):
def __init__(self, parser_generator: ParserGenerator):
self.gen = parser_generator
self.cache: Dict[Any, Any] = {}
def visit_NameLeaf(self, node: NameLeaf) -> Tuple[Optional[str], str]:
name = node.value
if name in ("NAME", "NUMBER", "STRING", "OP"):
name = name.lower()
return name, f"self.{name}()"
if name in ("NEWLINE", "DEDENT", "INDENT", "ENDMARKER", "ASYNC", "AWAIT"):
return name.lower(), f"self.expect({name!r})"
return name, f"self.{name}()"
def visit_StringLeaf(self, node: StringLeaf) -> Tuple[str, str]:
return "literal", f"self.expect({node.value})"
def visit_Rhs(self, node: Rhs) -> Tuple[Optional[str], str]:
if node in self.cache:
return self.cache[node]
if len(node.alts) == 1 and len(node.alts[0].items) == 1:
self.cache[node] = self.visit(node.alts[0].items[0])
else:
name = self.gen.name_node(node)
self.cache[node] = name, f"self.{name}()"
return self.cache[node]
def visit_NamedItem(self, node: NamedItem) -> Tuple[Optional[str], str]:
name, call = self.visit(node.item)
if node.name:
name = node.name
return name, call
def lookahead_call_helper(self, node: Lookahead) -> Tuple[str, str]:
name, call = self.visit(node.node)
head, tail = call.split("(", 1)
assert tail[-1] == ")"
tail = tail[:-1]
return head, tail
def visit_PositiveLookahead(self, node: PositiveLookahead) -> Tuple[None, str]:
head, tail = self.lookahead_call_helper(node)
return None, f"self.positive_lookahead({head}, {tail})"
def visit_NegativeLookahead(self, node: NegativeLookahead) -> Tuple[None, str]:
head, tail = self.lookahead_call_helper(node)
return None, f"self.negative_lookahead({head}, {tail})"
def visit_Opt(self, node: Opt) -> Tuple[str, str]:
name, call = self.visit(node.node)
return "opt", f"{call}," # Note trailing comma!
def visit_Repeat0(self, node: Repeat0) -> Tuple[str, str]:
if node in self.cache:
return self.cache[node]
name = self.gen.name_loop(node.node, False)
self.cache[node] = name, f"self.{name}()," # Also a trailing comma!
return self.cache[node]
def visit_Repeat1(self, node: Repeat1) -> Tuple[str, str]:
if node in self.cache:
return self.cache[node]
name = self.gen.name_loop(node.node, True)
self.cache[node] = name, f"self.{name}()" # But no trailing comma here!
return self.cache[node]
def visit_Gather(self, node: Gather) -> Tuple[str, str]:
if node in self.cache:
return self.cache[node]
name = self.gen.name_gather(node)
self.cache[node] = name, f"self.{name}()" # No trailing comma here either!
return self.cache[node]
def visit_Group(self, node: Group) -> Tuple[Optional[str], str]:
return self.visit(node.rhs)
def visit_Cut(self, node: Cut) -> Tuple[str, str]:
return "cut", "True"
class PythonParserGenerator(ParserGenerator, GrammarVisitor):
def __init__(self, grammar: grammar.Grammar, file: Optional[IO[Text]]):
super().__init__(grammar, file)
self.callmakervisitor = PythonCallMakerVisitor(self)
def generate(self, filename: str) -> None:
header = self.grammar.metas.get("header", MODULE_PREFIX)
if header is not None:
self.print(header.rstrip("\n").format(filename=filename))
subheader = self.grammar.metas.get("subheader", "")
if subheader:
self.print(subheader.format(filename=filename))
self.print("class GeneratedParser(Parser):")
while self.todo:
for rulename, rule in list(self.todo.items()):
del self.todo[rulename]
self.print()
with self.indent():
self.visit(rule)
trailer = self.grammar.metas.get("trailer", MODULE_SUFFIX)
if trailer is not None:
self.print(trailer.rstrip("\n"))
def visit_Rule(self, node: Rule) -> None:
is_loop = node.is_loop()
is_gather = node.is_gather()
rhs = node.flatten()
if node.left_recursive:
if node.leader:
self.print("@memoize_left_rec")
else:
# Non-leader rules in a cycle are not memoized,
# but they must still be logged.
self.print("@logger")
else:
self.print("@memoize")
node_type = node.type or "Any"
self.print(f"def {node.name}(self) -> Optional[{node_type}]:")
with self.indent():
self.print(f"# {node.name}: {rhs}")
if node.nullable:
self.print(f"# nullable={node.nullable}")
self.print("mark = self.mark()")
if is_loop:
self.print("children = []")
self.visit(rhs, is_loop=is_loop, is_gather=is_gather)
if is_loop:
self.print("return children")
else:
self.print("return None")
def visit_NamedItem(self, node: NamedItem, names: List[str]) -> None:
name, call = self.callmakervisitor.visit(node.item)
if node.name:
name = node.name
if not name:
self.print(call)
else:
if name != "cut":
name = dedupe(name, names)
self.print(f"({name} := {call})")
def visit_Rhs(self, node: Rhs, is_loop: bool = False, is_gather: bool = False) -> None:
if is_loop:
assert len(node.alts) == 1
for alt in node.alts:
self.visit(alt, is_loop=is_loop, is_gather=is_gather)
def visit_Alt(self, node: Alt, is_loop: bool, is_gather: bool) -> None:
names: List[str] = []
self.print("cut = False") # TODO: Only if needed.
if is_loop:
self.print("while (")
else:
self.print("if (")
with self.indent():
first = True
for item in node.items:
if first:
first = False
else:
self.print("and")
self.visit(item, names=names)
self.print("):")
with self.indent():
action = node.action
if not action:
if is_gather:
assert len(names) == 2
action = f"[{names[0]}] + {names[1]}"
else:
action = f"[{', '.join(names)}]"
if is_loop:
self.print(f"children.append({action})")
self.print(f"mark = self.mark()")
else:
self.print(f"return {action}")
self.print("self.reset(mark)")
# Skip remaining alternatives if a cut was reached.
self.print("if cut: return None") # TODO: Only if needed.

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# Adapted from mypy (mypy/build.py) under the MIT license.
from typing import *
def strongly_connected_components(
vertices: AbstractSet[str], edges: Dict[str, AbstractSet[str]]
) -> Iterator[AbstractSet[str]]:
"""Compute Strongly Connected Components of a directed graph.
Args:
vertices: the labels for the vertices
edges: for each vertex, gives the target vertices of its outgoing edges
Returns:
An iterator yielding strongly connected components, each
represented as a set of vertices. Each input vertex will occur
exactly once; vertices not part of a SCC are returned as
singleton sets.
From http://code.activestate.com/recipes/578507/.
"""
identified: Set[str] = set()
stack: List[str] = []
index: Dict[str, int] = {}
boundaries: List[int] = []
def dfs(v: str) -> Iterator[Set[str]]:
index[v] = len(stack)
stack.append(v)
boundaries.append(index[v])
for w in edges[v]:
if w not in index:
yield from dfs(w)
elif w not in identified:
while index[w] < boundaries[-1]:
boundaries.pop()
if boundaries[-1] == index[v]:
boundaries.pop()
scc = set(stack[index[v] :])
del stack[index[v] :]
identified.update(scc)
yield scc
for v in vertices:
if v not in index:
yield from dfs(v)
def topsort(
data: Dict[AbstractSet[str], Set[AbstractSet[str]]]
) -> Iterable[AbstractSet[AbstractSet[str]]]:
"""Topological sort.
Args:
data: A map from SCCs (represented as frozen sets of strings) to
sets of SCCs, its dependencies. NOTE: This data structure
is modified in place -- for normalization purposes,
self-dependencies are removed and entries representing
orphans are added.
Returns:
An iterator yielding sets of SCCs that have an equivalent
ordering. NOTE: The algorithm doesn't care about the internal
structure of SCCs.
Example:
Suppose the input has the following structure:
{A: {B, C}, B: {D}, C: {D}}
This is normalized to:
{A: {B, C}, B: {D}, C: {D}, D: {}}
The algorithm will yield the following values:
{D}
{B, C}
{A}
From http://code.activestate.com/recipes/577413/.
"""
# TODO: Use a faster algorithm?
for k, v in data.items():
v.discard(k) # Ignore self dependencies.
for item in set.union(*data.values()) - set(data.keys()):
data[item] = set()
while True:
ready = {item for item, dep in data.items() if not dep}
if not ready:
break
yield ready
data = {item: (dep - ready) for item, dep in data.items() if item not in ready}
assert not data, "A cyclic dependency exists amongst %r" % data
def find_cycles_in_scc(
graph: Dict[str, AbstractSet[str]], scc: AbstractSet[str], start: str
) -> Iterable[List[str]]:
"""Find cycles in SCC emanating from start.
Yields lists of the form ['A', 'B', 'C', 'A'], which means there's
a path from A -> B -> C -> A. The first item is always the start
argument, but the last item may be another element, e.g. ['A',
'B', 'C', 'B'] means there's a path from A to B and there's a
cycle from B to C and back.
"""
# Basic input checks.
assert start in scc, (start, scc)
assert scc <= graph.keys(), scc - graph.keys()
# Reduce the graph to nodes in the SCC.
graph = {src: {dst for dst in dsts if dst in scc} for src, dsts in graph.items() if src in scc}
assert start in graph
# Recursive helper that yields cycles.
def dfs(node: str, path: List[str]) -> Iterator[List[str]]:
if node in path:
yield path + [node]
return
path = path + [node] # TODO: Make this not quadratic.
for child in graph[node]:
yield from dfs(child, path)
yield from dfs(start, [])

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import importlib.util
import io
import os
import pathlib
import sys
import textwrap
import tokenize
from typing import Any, cast, Dict, IO, Type, Final
from pegen.build import compile_c_extension
from pegen.c_generator import CParserGenerator
from pegen.grammar import Grammar
from pegen.grammar_parser import GeneratedParser as GrammarParser
from pegen.parser import Parser
from pegen.python_generator import PythonParserGenerator
from pegen.tokenizer import Tokenizer
def generate_parser(grammar: Grammar) -> Type[Parser]:
# Generate a parser.
out = io.StringIO()
genr = PythonParserGenerator(grammar, out)
genr.generate("<string>")
# Load the generated parser class.
ns: Dict[str, Any] = {}
exec(out.getvalue(), ns)
return ns["GeneratedParser"]
def run_parser(file: IO[bytes], parser_class: Type[Parser], *, verbose: bool = False) -> Any:
# Run a parser on a file (stream).
tokenizer = Tokenizer(tokenize.generate_tokens(file.readline)) # type: ignore # typeshed issue #3515
parser = parser_class(tokenizer, verbose=verbose)
result = parser.start()
if result is None:
raise parser.make_syntax_error()
return result
def parse_string(
source: str, parser_class: Type[Parser], *, dedent: bool = True, verbose: bool = False
) -> Any:
# Run the parser on a string.
if dedent:
source = textwrap.dedent(source)
file = io.StringIO(source)
return run_parser(file, parser_class, verbose=verbose) # type: ignore # typeshed issue #3515
def make_parser(source: str) -> Type[Parser]:
# Combine parse_string() and generate_parser().
grammar = parse_string(source, GrammarParser)
return generate_parser(grammar)
def import_file(full_name: str, path: str) -> Any:
"""Import a python module from a path"""
spec = importlib.util.spec_from_file_location(full_name, path)
mod = importlib.util.module_from_spec(spec)
# We assume this is not None and has an exec_module() method.
# See https://docs.python.org/3/reference/import.html?highlight=exec_module#loading
loader = cast(Any, spec.loader)
loader.exec_module(mod)
return mod
def generate_c_parser_source(grammar: Grammar) -> str:
out = io.StringIO()
genr = CParserGenerator(grammar, out)
genr.generate("<string>")
return out.getvalue()
def generate_parser_c_extension(
grammar: Grammar, path: pathlib.PurePath, debug: bool = False
) -> Any:
"""Generate a parser c extension for the given grammar in the given path
Returns a module object with a parse_string() method.
TODO: express that using a Protocol.
"""
# Make sure that the working directory is empty: reusing non-empty temporary
# directories when generating extensions can lead to segmentation faults.
# Check issue #95 (https://github.com/gvanrossum/pegen/issues/95) for more
# context.
assert not os.listdir(path)
source = path / "parse.c"
with open(source, "w") as file:
genr = CParserGenerator(grammar, file, debug=debug)
genr.generate("parse.c")
extension_path = compile_c_extension(str(source), build_dir=str(path / "build"))
extension = import_file("parse", extension_path)
return extension
def print_memstats() -> bool:
MiB: Final = 2 ** 20
try:
import psutil # type: ignore
except ImportError:
return False
print("Memory stats:")
process = psutil.Process()
meminfo = process.memory_info()
res = {}
res["rss"] = meminfo.rss / MiB
res["vms"] = meminfo.vms / MiB
if sys.platform == "win32":
res["maxrss"] = meminfo.peak_wset / MiB
else:
# See https://stackoverflow.com/questions/938733/total-memory-used-by-python-process
import resource # Since it doesn't exist on Windows.
rusage = resource.getrusage(resource.RUSAGE_SELF)
if sys.platform == "darwin":
factor = 1
else:
factor = 1024 # Linux
res["maxrss"] = rusage.ru_maxrss * factor / MiB
for key, value in res.items():
print(f" {key:12.12s}: {value:10.0f} MiB")
return True

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import token
import tokenize
from typing import List, Iterator
Mark = int # NewType('Mark', int)
exact_token_types = token.EXACT_TOKEN_TYPES # type: ignore
def shorttok(tok: tokenize.TokenInfo) -> str:
return "%-25.25s" % f"{tok.start[0]}.{tok.start[1]}: {token.tok_name[tok.type]}:{tok.string!r}"
class Tokenizer:
"""Caching wrapper for the tokenize module.
This is pretty tied to Python's syntax.
"""
_tokens: List[tokenize.TokenInfo]
def __init__(self, tokengen: Iterator[tokenize.TokenInfo], *, verbose: bool = False):
self._tokengen = tokengen
self._tokens = []
self._index = 0
self._verbose = verbose
if verbose:
self.report(False, False)
def getnext(self) -> tokenize.TokenInfo:
"""Return the next token and updates the index."""
cached = True
while self._index == len(self._tokens):
tok = next(self._tokengen)
if tok.type in (tokenize.NL, tokenize.COMMENT):
continue
if tok.type == token.ERRORTOKEN and tok.string.isspace():
continue
self._tokens.append(tok)
cached = False
tok = self._tokens[self._index]
self._index += 1
if self._verbose:
self.report(cached, False)
return tok
def peek(self) -> tokenize.TokenInfo:
"""Return the next token *without* updating the index."""
while self._index == len(self._tokens):
tok = next(self._tokengen)
if tok.type in (tokenize.NL, tokenize.COMMENT):
continue
if tok.type == token.ERRORTOKEN and tok.string.isspace():
continue
self._tokens.append(tok)
return self._tokens[self._index]
def diagnose(self) -> tokenize.TokenInfo:
if not self._tokens:
self.getnext()
return self._tokens[-1]
def mark(self) -> Mark:
return self._index
def reset(self, index: Mark) -> None:
if index == self._index:
return
assert 0 <= index <= len(self._tokens), (index, len(self._tokens))
old_index = self._index
self._index = index
if self._verbose:
self.report(True, index < old_index)
def report(self, cached: bool, back: bool) -> None:
if back:
fill = "-" * self._index + "-"
elif cached:
fill = "-" * self._index + ">"
else:
fill = "-" * self._index + "*"
if self._index == 0:
print(f"{fill} (Bof)")
else:
tok = self._tokens[self._index - 1]
print(f"{fill} {shorttok(tok)}")

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[tool.black]
line-length = 99
target_version = ['py38']
exclude = '''
(
/pegen/grammar_parser.py # generated file
| /test/test_data/ # test files
)
'''

2
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memory-profiler==0.57.0
psutil==5.7.0

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Tools/peg_generator/scripts/__init__.py Normal file
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# This exists to let mypy find modules here

28
Tools/peg_generator/scripts/ast_timings.py Normal file
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import ast
import sys
import time
import token
import tokenize
from pegen.testutil import print_memstats
def main() -> None:
t0 = time.time()
for filename in sys.argv[1:]:
print(filename, end="\r")
try:
with open(filename) as file:
source = file.read()
tree = ast.parse(source, filename)
except Exception as err:
print(f"{filename}: {err.__class__.__name__}: {err}", file=sys.stderr)
tok = None
t1 = time.time()
dt = t1 - t0
print(f"Parsed in {dt:.3f} secs", file=sys.stderr)
print_memstats()
if __name__ == "__main__":
main()

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Tools/peg_generator/scripts/benchmark.py Normal file
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#!/usr/bin/env python3.9
import argparse
import ast
import sys
import os
import resource
from time import time
import memory_profiler
sys.path.insert(0, os.getcwd())
from peg_extension import parse
from pegen.build import build_parser_and_generator
from scripts.test_parse_directory import parse_directory
argparser = argparse.ArgumentParser(
prog="benchmark", description="Reproduce the various pegen benchmarks"
)
argparser.add_argument(
"--parser",
action="store",
choices=["pegen", "cpython"],
default="pegen",
help="Which parser to benchmark (default is pegen)",
)
argparser.add_argument(
"--target",
action="store",
choices=["xxl", "stdlib"],
default="xxl",
help="Which target to use for the benchmark (default is xxl.py)",
)
subcommands = argparser.add_subparsers(title="Benchmarks", dest="subcommand")
command_compile = subcommands.add_parser(
"compile", help="Benchmark parsing and compiling to bytecode"
)
command_parse = subcommands.add_parser("parse", help="Benchmark parsing and generating an ast.AST")
command_check = subcommands.add_parser(
"check", help="Benchmark parsing and throwing the tree away"
)
def benchmark(func):
def wrapper(*args):
times = list()
for _ in range(3):
start = time()
result = func(*args)
end = time()
times.append(end - start)
memory = memory_profiler.memory_usage((func, args))
print(f"{func.__name__}")
print(f"\tTime: {sum(times)/3:.3f} seconds on an average of 3 runs")
print(f"\tMemory: {max(memory)} MiB on an average of 3 runs")
return result
return wrapper
@benchmark
def time_compile(source, parser):
if parser == "cpython":
return compile(source, os.path.join("data", "xxl.py"), "exec")
else:
return parse.parse_string(source, mode=2)
@benchmark
def time_parse(source, parser):
if parser == "cpython":
return ast.parse(source, os.path.join("data", "xxl.py"), "exec")
else:
return parse.parse_string(source, mode=1)
@benchmark
def time_check(source):
return parse.parse_string(source, mode=0)
def run_benchmark_xxl(subcommand, parser, source):
if subcommand == "compile":
time_compile(source, parser)
elif subcommand == "parse":
time_parse(source, parser)
elif subcommand == "check":
time_check(source)
def run_benchmark_stdlib(subcommand, parser):
modes = {"compile": 2, "parse": 1, "check": 0}
extension = None
if parser == "pegen":
extension = build_parser_and_generator(
"../../Grammar/python.gram",
"peg_extension/parse.c",
compile_extension=True,
skip_actions=False,
)
for _ in range(3):
parse_directory(
"../../Lib",
"../../Grammar/python.gram",
verbose=False,
excluded_files=[
"*/bad*",
"*/lib2to3/tests/data/*",
],
skip_actions=False,
tree_arg=0,
short=True,
extension=extension,
mode=modes[subcommand],
parser=parser,
)
def main():
args = argparser.parse_args()
subcommand = args.subcommand
parser = args.parser
target = args.target
if subcommand is None:
argparser.error("A benchmark to run is required")
if subcommand == "check" and parser == "cpython":
argparser.error("Cannot use check target with the CPython parser")
if target == "xxl":
with open(os.path.join("data", "xxl.py"), "r") as f:
source = f.read()
run_benchmark_xxl(subcommand, parser, source)
elif target == "stdlib":
run_benchmark_stdlib(subcommand, parser)
if __name__ == "__main__":
main()

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Tools/peg_generator/scripts/download_pypi_packages.py Executable file
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#!/usr/bin/env python3.8
import argparse
import os
import json
from typing import Dict, Any
from urllib.request import urlretrieve
argparser = argparse.ArgumentParser(
prog="download_pypi_packages", description="Helper program to download PyPI packages",
)
argparser.add_argument(
"-n", "--number", type=int, default=100, help="Number of packages to download"
)
argparser.add_argument(
"-a", "--all", action="store_true", help="Download all packages listed in the json file"
)
def load_json(filename: str) -> Dict[Any, Any]:
with open(os.path.join("data", f"{filename}.json"), "r") as f:
j = json.loads(f.read())
return j
def remove_json(filename: str) -> None:
path = os.path.join("data", f"{filename}.json")
os.remove(path)
def download_package_json(package_name: str) -> None:
url = f"https://pypi.org/pypi/{package_name}/json"
urlretrieve(url, os.path.join("data", f"{package_name}.json"))
def download_package_code(name: str, package_json: Dict[Any, Any]) -> None:
source_index = -1
for idx, url_info in enumerate(package_json["urls"]):
if url_info["python_version"] == "source":
source_index = idx
break
filename = package_json["urls"][source_index]["filename"]
url = package_json["urls"][source_index]["url"]
urlretrieve(url, os.path.join("data", "pypi", filename))
def main() -> None:
args = argparser.parse_args()
number_packages = args.number
all_packages = args.all
top_pypi_packages = load_json("top-pypi-packages-365-days")
if all_packages:
top_pypi_packages = top_pypi_packages["rows"]
elif number_packages >= 0 and number_packages <= 4000:
top_pypi_packages = top_pypi_packages["rows"][:number_packages]
else:
raise AssertionError("Unknown value for NUMBER_OF_PACKAGES")
try:
os.mkdir(os.path.join("data", "pypi"))
except FileExistsError:
pass
for package in top_pypi_packages:
package_name = package["project"]
print(f"Downloading JSON Data for {package_name}... ", end="")
download_package_json(package_name)
print("Done")
package_json = load_json(package_name)
try:
print(f"Dowloading and compressing package {package_name} ... ", end="")
download_package_code(package_name, package_json)
print("Done")
except (IndexError, KeyError):
print(f"Could not locate source for {package_name}")
continue
finally:
remove_json(package_name)
if __name__ == "__main__":
main()

61
Tools/peg_generator/scripts/find_max_nesting.py Executable file
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#!/usr/bin/env python3.8
"""Find the maximum amount of nesting for an expression that can be parsed
without causing a parse error.
Starting at the INITIAL_NESTING_DEPTH, an expression containing n parenthesis
around a 0 is generated then tested with both the C and Python parsers. We
continue incrementing the number of parenthesis by 10 until both parsers have
failed. As soon as a single parser fails, we stop testing that parser.
The grammar file, initial nesting size, and amount by which the nested size is
incremented on each success can be controlled by changing the GRAMMAR_FILE,
INITIAL_NESTING_DEPTH, or NESTED_INCR_AMT variables.
Usage: python -m scripts.find_max_nesting
"""
import os
import sys
from tempfile import TemporaryDirectory
from pathlib import Path
from typing import Any
from _peg_parser import parse_string
GRAMMAR_FILE = "data/python.gram"
INITIAL_NESTING_DEPTH = 10
NESTED_INCR_AMT = 10
FAIL = "\033[91m"
ENDC = "\033[0m"
def check_nested_expr(nesting_depth: int) -> bool:
expr = f"{'(' * nesting_depth}0{')' * nesting_depth}"
try:
parse_string(expr)
print(f"Nesting depth of {nesting_depth} is successful")
return True
except Exception as err:
print(f"{FAIL}(Failed with nesting depth of {nesting_depth}{ENDC}")
print(f"{FAIL}\t{err}{ENDC}")
return False
def main() -> None:
print(f"Testing {GRAMMAR_FILE} starting at nesting depth of {INITIAL_NESTING_DEPTH}...")
nesting_depth = INITIAL_NESTING_DEPTH
succeeded = True
while succeeded:
expr = f"{'(' * nesting_depth}0{')' * nesting_depth}"
if succeeded:
succeeded = check_nested_expr(nesting_depth)
nesting_depth += NESTED_INCR_AMT
sys.exit(1)
if __name__ == "__main__":
main()

111
Tools/peg_generator/scripts/grammar_grapher.py Executable file
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#!/usr/bin/env python3.8
""" Convert a grammar into a dot-file suitable for use with GraphViz
For example:
Generate the GraphViz file:
# scripts/grammar_grapher.py data/python.gram > python.gv
Then generate the graph...
# twopi python.gv -Tpng > python_twopi.png
or
# dot python.gv -Tpng > python_dot.png
NOTE: The _dot_ and _twopi_ tools seem to produce the most useful results.
The _circo_ tool is the worst of the bunch. Don't even bother.
"""
import argparse
import sys
from typing import Any, List
sys.path.insert(0, ".")
from pegen.build import build_parser
from pegen.grammar import (
Alt,
Cut,
Grammar,
Group,
Leaf,
Lookahead,
Rule,
NameLeaf,
NamedItem,
Opt,
Repeat,
Rhs,
)
argparser = argparse.ArgumentParser(prog="graph_grammar", description="Graph a grammar tree",)
argparser.add_argument("grammar_file", help="The grammar file to graph")
def references_for_item(item: Any) -> List[Any]:
if isinstance(item, Alt):
return [_ref for _item in item.items for _ref in references_for_item(_item)]
elif isinstance(item, Cut):
return []
elif isinstance(item, Group):
return references_for_item(item.rhs)
elif isinstance(item, Lookahead):
return references_for_item(item.node)
elif isinstance(item, NamedItem):
return references_for_item(item.item)
# NOTE NameLeaf must be before Leaf
elif isinstance(item, NameLeaf):
if item.value == "ENDMARKER":
return []
return [item.value]
elif isinstance(item, Leaf):
return []
elif isinstance(item, Opt):
return references_for_item(item.node)
elif isinstance(item, Repeat):
return references_for_item(item.node)
elif isinstance(item, Rhs):
return [_ref for alt in item.alts for _ref in references_for_item(alt)]
elif isinstance(item, Rule):
return references_for_item(item.rhs)
else:
raise RuntimeError(f"Unknown item: {type(item)}")
def main() -> None:
args = argparser.parse_args()
try:
grammar, parser, tokenizer = build_parser(args.grammar_file)
except Exception as err:
print("ERROR: Failed to parse grammar file", file=sys.stderr)
sys.exit(1)
references = {}
for name, rule in grammar.rules.items():
references[name] = set(references_for_item(rule))
# Flatten the start node if has only a single reference
root_node = "start"
if start := references["start"]:
if len(start) == 1:
root_node = list(start)[0]
del references["start"]
print("digraph g1 {")
print('\toverlap="scale";') # Force twopi to scale the graph to avoid overlaps
print(f'\troot="{root_node}";')
print(f"\t{root_node} [color=green, shape=circle]")
for name, refs in references.items():
if refs: # Ignore empty sets
print(f"\t{name} -> {','.join(refs)};")
print("}")
if __name__ == "__main__":
main()

66
Tools/peg_generator/scripts/joinstats.py Normal file
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#!/usr/bin/env python3.8
"""Produce a report about the most-memoable types.
Reads a list of statistics from stdin. Each line must be two numbers,
being a type and a count. We then read some other files and produce a
list sorted by most frequent type.
There should also be something to recognize left-recursive rules.
"""
import os
import re
import sys
from typing import Dict
reporoot = os.path.dirname(os.path.dirname(__file__))
parse_c = os.path.join(reporoot, "peg_extension", "parse.c")
class TypeMapper:
"""State used to map types to names."""
def __init__(self, filename: str) -> None:
self.table: Dict[int, str] = {}
with open(filename) as f:
for line in f:
match = re.match(r"#define (\w+)_type (\d+)", line)
if match:
name, type = match.groups()
if "left" in line.lower():
name += " // Left-recursive"
self.table[int(type)] = name
def lookup(self, type: int) -> str:
return self.table.get(type, str(type))
def main() -> None:
mapper = TypeMapper(parse_c)
table = []
filename = sys.argv[1]
with open(filename) as f:
for lineno, line in enumerate(f, 1):
line = line.strip()
if not line or line.startswith("#"):
continue
parts = line.split()
# Extra fields ignored
if len(parts) < 2:
print(f"{lineno}: bad input ({line!r})")
continue
try:
type, count = map(int, parts[:2])
except ValueError as err:
print(f"{lineno}: non-integer input ({line!r})")
continue
table.append((type, count))
table.sort(key=lambda values: -values[1])
for type, count in table:
print(f"{type:4d} {count:9d} {mapper.lookup(type)}")
if __name__ == "__main__":
main()

117
Tools/peg_generator/scripts/show_parse.py Executable file
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@ -0,0 +1,117 @@
#!/usr/bin/env python3.8
"""Show the parse tree for a given program, nicely formatted.
Example:
$ scripts/show_parse.py a+b
Module(
body=[
Expr(
value=BinOp(
left=Name(id="a", ctx=Load()), op=Add(), right=Name(id="b", ctx=Load())
)
)
],
type_ignores=[],
)
$
Use -v to show line numbers and column offsets.
The formatting is done using black. You can also import this module
and call one of its functions.
"""
import argparse
import ast
import difflib
import os
import sys
import tempfile
from typing import List
parser = argparse.ArgumentParser()
parser.add_argument(
"-d", "--diff", action="store_true", help="show diff between grammar and ast (requires -g)"
)
parser.add_argument("-g", "--grammar-file", help="grammar to use (default: use the ast module)")
parser.add_argument(
"-m",
"--multiline",
action="store_true",
help="concatenate program arguments using newline instead of space",
)
parser.add_argument("-v", "--verbose", action="store_true", help="show line/column numbers")
parser.add_argument("program", nargs="+", help="program to parse (will be concatenated)")
def format_tree(tree: ast.AST, verbose: bool = False) -> str:
with tempfile.NamedTemporaryFile("w+") as tf:
tf.write(ast.dump(tree, include_attributes=verbose))
tf.write("\n")
tf.flush()
cmd = f"black -q {tf.name}"
sts = os.system(cmd)
if sts:
raise RuntimeError(f"Command {cmd!r} failed with status 0x{sts:x}")
tf.seek(0)
return tf.read()
def diff_trees(a: ast.AST, b: ast.AST, verbose: bool = False) -> List[str]:
sa = format_tree(a, verbose)
sb = format_tree(b, verbose)
la = sa.splitlines()
lb = sb.splitlines()
return list(difflib.unified_diff(la, lb, "a", "b", lineterm=""))
def show_parse(source: str, verbose: bool = False) -> str:
tree = ast.parse(source)
return format_tree(tree, verbose).rstrip("\n")
def print_parse(source: str, verbose: bool = False) -> None:
print(show_parse(source, verbose))
def main() -> None:
args = parser.parse_args()
if args.diff and not args.grammar_file:
parser.error("-d/--diff requires -g/--grammar-file")
if args.multiline:
sep = "\n"
else:
sep = " "
program = sep.join(args.program)
if args.grammar_file:
sys.path.insert(0, os.curdir)
from pegen.build import build_parser_and_generator
build_parser_and_generator(args.grammar_file, "peg_parser/parse.c", compile_extension=True)
from pegen.parse import parse_string # type: ignore[import]
tree = parse_string(program, mode=1)
if args.diff:
a = tree
b = ast.parse(program)
diff = diff_trees(a, b, args.verbose)
if diff:
for line in diff:
print(line)
else:
print("# Trees are the same")
else:
print(f"# Parsed using {args.grammar_file}")
print(format_tree(tree, args.verbose))
else:
tree = ast.parse(program)
print("# Parse using ast.parse()")
print(format_tree(tree, args.verbose))
if __name__ == "__main__":
main()

289
Tools/peg_generator/scripts/test_parse_directory.py Executable file
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@ -0,0 +1,289 @@
#!/usr/bin/env python3.8
import argparse
import ast
import os
import sys
import tempfile
import time
import traceback
from glob import glob
from pathlib import PurePath
from typing import List, Optional, Any
sys.path.insert(0, os.getcwd())
from pegen.build import build_parser_and_generator
from pegen.testutil import print_memstats
from scripts import show_parse
SUCCESS = "\033[92m"
FAIL = "\033[91m"
ENDC = "\033[0m"
argparser = argparse.ArgumentParser(
prog="test_parse_directory",
description="Helper program to test directories or files for pegen",
)
argparser.add_argument("-d", "--directory", help="Directory path containing files to test")
argparser.add_argument("-g", "--grammar-file", help="Grammar file path")
argparser.add_argument(
"-e", "--exclude", action="append", default=[], help="Glob(s) for matching files to exclude"
)
argparser.add_argument(
"-s", "--short", action="store_true", help="Only show errors, in a more Emacs-friendly format"
)
argparser.add_argument(
"-v", "--verbose", action="store_true", help="Display detailed errors for failures"
)
argparser.add_argument(
"--skip-actions", action="store_true", help="Suppress code emission for rule actions",
)
argparser.add_argument(
"-t", "--tree", action="count", help="Compare parse tree to official AST", default=0
)
def report_status(
succeeded: bool,
file: str,
verbose: bool,
error: Optional[Exception] = None,
short: bool = False,
) -> None:
if short and succeeded:
return
if succeeded is True:
status = "OK"
COLOR = SUCCESS
else:
status = "Fail"
COLOR = FAIL
if short:
lineno = 0
offset = 0
if isinstance(error, SyntaxError):
lineno = error.lineno or 1
offset = error.offset or 1
message = error.args[0]
else:
message = f"{error.__class__.__name__}: {error}"
print(f"{file}:{lineno}:{offset}: {message}")
else:
print(f"{COLOR}{file:60} {status}{ENDC}")
if error and verbose:
print(f" {str(error.__class__.__name__)}: {error}")
def compare_trees(
actual_tree: ast.AST, file: str, verbose: bool, include_attributes: bool = False,
) -> int:
with open(file) as f:
expected_tree = ast.parse(f.read())
expected_text = ast.dump(expected_tree, include_attributes=include_attributes)
actual_text = ast.dump(actual_tree, include_attributes=include_attributes)
if actual_text == expected_text:
if verbose:
print("Tree for {file}:")
print(show_parse.format_tree(actual_tree, include_attributes))
return 0
print(f"Diffing ASTs for {file} ...")
expected = show_parse.format_tree(expected_tree, include_attributes)
actual = show_parse.format_tree(actual_tree, include_attributes)
if verbose:
print("Expected for {file}:")
print(expected)
print("Actual for {file}:")
print(actual)
print(f"Diff for {file}:")
diff = show_parse.diff_trees(expected_tree, actual_tree, include_attributes)
for line in diff:
print(line)
return 1
def parse_directory(
directory: str,
grammar_file: str,
verbose: bool,
excluded_files: List[str],
skip_actions: bool,
tree_arg: int,
short: bool,
extension: Any,
mode: int,
parser: str,
) -> int:
if parser == "cpython" and (tree_arg or mode == 0):
print("Cannot specify tree argument or mode=0 with the cpython parser.", file=sys.stderr)
return 1
if not directory:
print("You must specify a directory of files to test.", file=sys.stderr)
return 1
if grammar_file:
if not os.path.exists(grammar_file):
print(f"The specified grammar file, {grammar_file}, does not exist.", file=sys.stderr)
return 1
try:
if not extension and parser == "pegen":
build_parser_and_generator(
grammar_file,
"peg_extension/parse.c",
compile_extension=True,
skip_actions=skip_actions,
)
except Exception as err:
print(
f"{FAIL}The following error occurred when generating the parser. Please check your grammar file.\n{ENDC}",
file=sys.stderr,
)
traceback.print_exception(err.__class__, err, None)
return 1
else:
print("A grammar file was not provided - attempting to use existing file...\n")
if parser == "pegen":
try:
from peg_extension import parse # type: ignore
except:
print(
"An existing parser was not found. Please run `make` or specify a grammar file with the `-g` flag.",
file=sys.stderr,
)
return 1
# For a given directory, traverse files and attempt to parse each one
# - Output success/failure for each file
errors = 0
files = []
trees = {} # Trees to compare (after everything else is done)
t0 = time.time()
for file in sorted(glob(f"{directory}/**/*.py", recursive=True)):
# Only attempt to parse Python files and files that are not excluded
should_exclude_file = False
for pattern in excluded_files:
if PurePath(file).match(pattern):
should_exclude_file = True
break
if not should_exclude_file:
try:
if tree_arg:
mode = 1
if parser == "cpython":
with open(file, "r") as f:
source = f.read()
if mode == 2:
compile(source, file, "exec")
elif mode == 1:
ast.parse(source, file, "exec")
else:
tree = parse.parse_file(file, mode=mode)
if tree_arg:
trees[file] = tree
if not short:
report_status(succeeded=True, file=file, verbose=verbose)
except Exception as error:
try:
ast.parse(file)
except Exception:
if not short:
print(f"File {file} cannot be parsed by either pegen or the ast module.")
else:
report_status(
succeeded=False, file=file, verbose=verbose, error=error, short=short
)
errors += 1
files.append(file)
t1 = time.time()
total_seconds = t1 - t0
total_files = len(files)
total_bytes = 0
total_lines = 0
for file in files:
# Count lines and bytes separately
with open(file, "rb") as f:
total_lines += sum(1 for _ in f)
total_bytes += f.tell()
print(
f"Checked {total_files:,} files, {total_lines:,} lines,",
f"{total_bytes:,} bytes in {total_seconds:,.3f} seconds.",
)
if total_seconds > 0:
print(
f"That's {total_lines / total_seconds :,.0f} lines/sec,",
f"or {total_bytes / total_seconds :,.0f} bytes/sec.",
)
if parser == "pegen":
# Dump memo stats to @data.
with open("@data", "w") as datafile:
for i, count in enumerate(parse.get_memo_stats()):
if count:
datafile.write(f"{i:4d} {count:9d}\n")
if short:
print_memstats()
if errors:
print(f"Encountered {errors} failures.", file=sys.stderr)
# Compare trees (the dict is empty unless -t is given)
compare_trees_errors = 0
for file, tree in trees.items():
if not short:
print("Comparing ASTs for", file)
if compare_trees(tree, file, verbose, tree_arg >= 2) == 1:
compare_trees_errors += 1
if errors or compare_trees_errors:
return 1
return 0
def main() -> None:
args = argparser.parse_args()
directory = args.directory
grammar_file = args.grammar_file
verbose = args.verbose
excluded_files = args.exclude
skip_actions = args.skip_actions
tree = args.tree
short = args.short
sys.exit(
parse_directory(
directory,
grammar_file,
verbose,
excluded_files,
skip_actions,
tree,
short,
None,
0,
"pegen",
)
)
if __name__ == "__main__":
main()

101
Tools/peg_generator/scripts/test_pypi_packages.py Executable file
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@ -0,0 +1,101 @@
#!/usr/bin/env python3.8
import argparse
import os
import glob
import tarfile
import zipfile
import shutil
import sys
from typing import Generator, Any
sys.path.insert(0, ".")
from pegen import build
from scripts import test_parse_directory
argparser = argparse.ArgumentParser(
prog="test_pypi_packages", description="Helper program to test parsing PyPI packages",
)
argparser.add_argument(
"-t", "--tree", action="count", help="Compare parse tree to official AST", default=0
)
def get_packages() -> Generator[str, None, None]:
all_packages = (
glob.glob("./data/pypi/*.tar.gz")
+ glob.glob("./data/pypi/*.zip")
+ glob.glob("./data/pypi/*.tgz")
)
for package in all_packages:
yield package
def extract_files(filename: str) -> None:
savedir = os.path.join("data", "pypi")
if tarfile.is_tarfile(filename):
tarfile.open(filename).extractall(savedir)
elif zipfile.is_zipfile(filename):
zipfile.ZipFile(filename).extractall(savedir)
else:
raise ValueError(f"Could not identify type of compressed file {filename}")
def find_dirname(package_name: str) -> str:
for name in os.listdir(os.path.join("data", "pypi")):
full_path = os.path.join("data", "pypi", name)
if os.path.isdir(full_path) and name in package_name:
return full_path
assert False # This is to fix mypy, should never be reached
def run_tests(dirname: str, tree: int, extension: Any) -> int:
return test_parse_directory.parse_directory(
dirname,
"data/python.gram",
verbose=False,
excluded_files=[
"*/failset/*",
"*/failset/**",
"*/failset/**/*",
"*/test2to3/*",
"*/test2to3/**/*",
"*/bad*",
"*/lib2to3/tests/data/*",
],
skip_actions=False,
tree_arg=tree,
short=True,
extension=extension,
)
def main() -> None:
args = argparser.parse_args()
tree = args.tree
extension = build.build_parser_and_generator(
"data/python.gram", "peg_parser/parse.c", compile_extension=True
)
for package in get_packages():
print(f"Extracting files from {package}... ", end="")
try:
extract_files(package)
print("Done")
except ValueError as e:
print(e)
continue
print(f"Trying to parse all python files ... ")
dirname = find_dirname(package)
status = run_tests(dirname, tree, extension)
if status == 0:
print("Done")
shutil.rmtree(dirname)
else:
print(f"Failed to parse {dirname}")
if __name__ == "__main__":
main()

4
Tools/scripts/run_tests.py
View File

@ -25,8 +25,10 @@ def main(regrtest_args):
'-u', # Unbuffered stdout and stderr
'-W', 'default', # Warnings set to 'default'
'-bb', # Warnings about bytes/bytearray
'-E', # Ignore environment variables
]
if 'PYTHONOLDPARSER' not in os.environ:
args.append('-E') # Ignore environment variables
# Allow user-specified interpreter options to override our defaults.
args.extend(test.support.args_from_interpreter_flags())