If a "=" is specified a the end of an f-string expression, the f-string will evaluate to the text of the expression, followed by '=', followed by the repr of the value of the expression.
This commit contains the implementation of PEP570: Python positional-only parameters.
* Update Grammar/Grammar with new typedarglist and varargslist
* Regenerate grammar files
* Update and regenerate AST related files
* Update code object
* Update marshal.c
* Update compiler and symtable
* Regenerate importlib files
* Update callable objects
* Implement positional-only args logic in ceval.c
* Regenerate frozen data
* Update standard library to account for positional-only args
* Add test file for positional-only args
* Update other test files to account for positional-only args
* Add News entry
* Update inspect module and related tests
This adds a `feature_version` flag to `ast.parse()` (documented) and `compile()` (hidden) that allow tweaking the parser to support older versions of the grammar. In particular if `feature_version` is 5 or 6, the hacks for the `async` and `await` keyword from PEP 492 are reinstated. (For 7 or higher, these are unconditionally treated as keywords, but they are still special tokens rather than `NAME` tokens that the parser driver recognizes.)
https://bugs.python.org/issue35975
* Add tokenization of :=
- Add token to Include/token.h. Add token to documentation in Doc/library/token.rst.
- Run `./python Lib/token.py` to regenerate Lib/token.py.
- Update Parser/tokenizer.c: add case to handle `:=`.
* Add initial usage of := in grammar.
* Update Python.asdl to match the grammar updates. Regenerated Include/Python-ast.h and Python/Python-ast.c
* Update AST and compiler files in Python/ast.c and Python/compile.c. Basic functionality, this isn't scoped properly
* Regenerate Lib/symbol.py using `./python Lib/symbol.py`
* Tests - Fix failing tests in test_parser.py due to changes in token numbers for internal representation
* Tests - Add simple test for := token
* Tests - Add simple tests for named expressions using expr and suite
* Tests - Update number of levels for nested expressions to prevent stack overflow
* Update symbol table to handle NamedExpr
* Update Grammar to allow assignment expressions in if statements.
Regenerate Python/graminit.c accordingly using `make regen-grammar`
* Tests - Add additional tests for named expressions in RoundtripLegalSyntaxTestCase, based on examples and information directly from PEP 572
Note: failing tests are currently commented out (4 out of 24 tests currently fail)
* Tests - Add temporary syntax test failure tests in test_parser.py
Note: There is an outstanding TODO for this -- syntax tests need to be
moved to a different file (presumably test_syntax.py), but this is
covering what needs to be tested at the moment, and it's more convenient
to run a single test for the time being
* Add support for allowing assignment expressions as function argument annotations. Uncomment tests for these cases because they all pass now!
* Tests - Move existing syntax tests out of test_parser.py and into test_named_expressions.py. Refactor syntax tests to use unittest
* Add TargetScopeError exception to extend SyntaxError
Note: This simply creates the TargetScopeError exception, it is not yet
used anywhere
* Tests - Update tests per PEP 572
Continue refactoring test suite:
The named expression test suite now checks for any invalid cases that
throw exceptions (no longer limited to SyntaxErrors), assignment tests
to ensure that variables are properly assigned, and scope tests to
ensure that variable availability and values are correct
Note:
- There are still tests that are marked to skip, as they are not yet
implemented
- There are approximately 300 lines of the PEP that have not yet been
addressed, though these may be deferred
* Documentation - Small updates to XXX/todo comments
- Remove XXX from child description in ast.c
- Add comment with number of previously supported nested expressions for
3.7.X in test_parser.py
* Fix assert in seq_for_testlist()
* Cleanup - Denote "Not implemented -- No keyword args" on failing test case. Fix PEP8 error for blank lines at beginning of test classes in test_parser.py
* Tests - Wrap all file opens in `with...as` to ensure files are closed
* WIP: handle f(a := 1)
* Tests and Cleanup - No longer skips keyword arg test. Keyword arg test now uses a simpler test case and does not rely on an external file. Remove print statements from ast.c
* Tests - Refactor last remaining test case that relied on on external file to use a simpler test case without the dependency
* Tests - Add better description of remaning skipped tests. Add test checking scope when using assignment expression in a function argument
* Tests - Add test for nested comprehension, testing value and scope. Fix variable name in skipped comprehension scope test
* Handle restriction of LHS for named expressions - can only assign to LHS of type NAME. Specifically, restrict assignment to tuples
This adds an alternative set_context specifically for named expressions,
set_namedexpr_context. Thus, context is now set differently for standard
assignment versus assignment for named expressions in order to handle
restrictions.
* Tests - Update negative test case for assigning to lambda to match new error message. Add negative test case for assigning to tuple
* Tests - Reorder test cases to group invalid syntax cases and named assignment target errors
* Tests - Update test case for named expression in function argument - check that result and variable are set correctly
* Todo - Add todo for TargetScopeError based on Guido's comment (2b3acd37bd (r30472562))
* Tests - Add named expression tests for assignment operator in function arguments
Note: One of two tests are skipped, as function arguments are currently treating
an assignment expression inside of parenthesis as one child, which does
not properly catch the named expression, nor does it count arguments
properly
* Add NamedStore to expr_context. Regenerate related code with `make regen-ast`
* Add usage of NamedStore to ast_for_named_expr in ast.c. Update occurances of checking for Store to also handle NamedStore where appropriate
* Add ste_comprehension to _symtable_entry to track if the namespace is a comprehension. Initialize ste_comprehension to 0. Set set_comprehension to 1 in symtable_handle_comprehension
* s/symtable_add_def/symtable_add_def_helper. Add symtable_add_def to handle grabbing st->st_cur and passing it to symtable_add_def_helper. This now allows us to call the original code from symtable_add_def by instead calling symtable_add_def_helper with a different ste.
* Refactor symtable_record_directive to take lineno and col_offset as arguments instead of stmt_ty. This allows symtable_record_directive to be used for stmt_ty and expr_ty
* Handle elevating scope for named expressions in comprehensions.
* Handle error for usage of named expression inside a class block
* Tests - No longer skip scope tests. Add additional scope tests
* Cleanup - Update error message for named expression within a comprehension within a class. Update comments. Add assert for symtable_extend_namedexpr_scope to validate that we always find at least a ModuleScope if we don't find a Class or FunctionScope
* Cleanup - Add missing case for NamedStore in expr_context_name. Remove unused var in set_namedexpr_content
* Refactor - Consolidate set_context and set_namedexpr_context to reduce duplicated code. Special cases for named expressions are handled by checking if ctx is NamedStore
* Cleanup - Add additional use cases for ast_for_namedexpr in usage comment. Fix multiple blank lines in test_named_expressions
* Tests - Remove unnecessary test case. Renumber test case function names
* Remove TargetScopeError for now. Will add back if needed
* Cleanup - Small comment nit for consistency
* Handle positional argument check with named expression
* Add TargetScopeError exception definition. Add documentation for TargetScopeError in c-api docs. Throw TargetScopeError instead of SyntaxError when using a named expression in a comprehension within a class scope
* Increase stack size for parser by 200. This is a minimal change (approx. 5kb) and should not have an impact on any systems. Update parser test to allow 99 nested levels again
* Add TargetScopeError to exception_hierarchy.txt for test_baseexception.py_
* Tests - Major update for named expression tests, both in test_named_expressions and test_parser
- Add test for TargetScopeError
- Add tests for named expressions in comprehension scope and edge cases
- Add tests for named expressions in function arguments (declarations
and call sites)
- Reorganize tests to group them more logically
* Cleanup - Remove unnecessary comment
* Cleanup - Comment nitpicks
* Explicitly disallow assignment expressions to a name inside parentheses, e.g.: ((x) := 0)
- Add check for LHS types to detect a parenthesis then a name (see note)
- Add test for this scenario
- Update tests for changed error message for named assignment to a tuple
(also, see note)
Note: This caused issues with the previous error handling for named assignment
to a LHS that contained an expression, such as a tuple. Thus, the check
for the LHS of a named expression must be changed to be more specific if
we wish to maintain the previous error messages
* Cleanup - Wrap lines more strictly in test file
* Revert "Explicitly disallow assignment expressions to a name inside parentheses, e.g.: ((x) := 0)"
This reverts commit f1531400ca7d7a2d148830c8ac703f041740896d.
* Add NEWS.d entry
* Tests - Fix error in test_pickle.test_exceptions by adding TargetScopeError to list of exceptions
* Tests - Update error message tests to reflect improved messaging convention (s/can't/cannot)
* Remove cases that cannot be reached in compile.c. Small linting update.
* Update Grammar/Tokens to add COLONEQUAL. Regenerate all files
* Update TargetScopeError PRE_INIT and POST_INIT, as this was purposefully left out when fixing rebase conflicts
* Add NamedStore back and regenerate files
* Pass along line number and end col info for named expression
* Simplify News entry
* Fix compiler warning and explicity mark fallthrough
The majority of this PR is tediously passing `end_lineno` and `end_col_offset` everywhere. Here are non-trivial points:
* It is not possible to reconstruct end positions in AST "on the fly", some information is lost after an AST node is constructed, so we need two more attributes for every AST node `end_lineno` and `end_col_offset`.
* I add end position information to both CST and AST. Although it may be technically possible to avoid adding end positions to CST, the code becomes more cumbersome and less efficient.
* Since the end position is not known for non-leaf CST nodes while the next token is added, this requires a bit of extra care (see `_PyNode_FinalizeEndPos`). Unless I made some mistake, the algorithm should be linear.
* For statements, I "trim" the end position of suites to not include the terminal newlines and dedent (this seems to be what people would expect), for example in
```python
class C:
pass
pass
```
the end line and end column for the class definition is (2, 8).
* For `end_col_offset` I use the common Python convention for indexing, for example for `pass` the `end_col_offset` is 4 (not 3), so that `[0:4]` gives one the source code that corresponds to the node.
* I added a helper function `ast.get_source_segment()`, to get source text segment corresponding to a given AST node. It is also useful for testing.
An (inevitable) downside of this PR is that AST now takes almost 25% more memory. I think however it is probably justified by the benefits.
There are some same consts in a module. This commit merges them into
single instance. It reduces number of objects in memory after loading modules.
https://bugs.python.org/issue34100
* ast.h now includes Python-ast.h and node.h
* parsetok.h now includes node.h and grammar.h
* symtable.h now includes Python-ast.h
* Modify asdl_c.py to enhance Python-ast.h:
* Add #ifndef/#define Py_PYTHON_AST_H to be able to include the header
twice
* Add "extern { ... }" for C++
* Undefine "Yield" macro conflicting with winbase.h
* Remove "#undef Yield" from C files, it's now done in Python-ast.h
* Remove now useless includes in C files
Remove the docstring attribute of AST types and restore docstring
expression as a first stmt in their body.
Co-authored-by: INADA Naoki <methane@users.noreply.github.com>
* Added new opcode END_ASYNC_FOR.
* Setting global StopAsyncIteration no longer breaks "async for" loops.
* Jumping into an "async for" loop is now disabled.
* Jumping out of an "async for" loop no longer corrupts the stack.
* Simplify the compiler.
* Document `from __future__ import annotations`
* Provide plumbing and tests for `from __future__ import annotations`
* Implement unparsing the AST back to string form
This is required for PEP 563 and as such only implements a part of the
unparsing process that covers expressions.
Previously, CO_NOFREE was set in the compiler, which meant
it could end up being set incorrectly when code objects
were created directly. Setting it in the constructor based
on freevars and cellvars ensures it is always accurate,
regardless of how the code object is defined.
* Add Py_UNREACHABLE() as an alias to abort().
* Use Py_UNREACHABLE() instead of assert(0)
* Convert more unreachable code to use Py_UNREACHABLE()
* Document Py_UNREACHABLE() and a few other macros.
* bpo-29463: Add docstring field to some AST nodes.
ClassDef, ModuleDef, FunctionDef, and AsyncFunctionDef has docstring
field for now. It was first statement of there body.
* fix document. thanks travis!
* doc fixes
Special thanks to INADA Naoki for pushing the patch through
the last mile, Serhiy Storchaka for reviewing the code, and to
Victor Stinner for suggesting the idea (originally implemented
in the PyPy project).
Handling zero-argument super() in __init_subclass__ and
__set_name__ involved moving __class__ initialisation to
type.__new__. This requires cooperation from custom
metaclasses to ensure that the new __classcell__ entry
is passed along appropriately.
The initial implementation of that change resulted in abruptly
broken zero-argument super() support in metaclasses that didn't
adhere to the new requirements (such as Django's metaclass for
Model definitions).
The updated approach adopted here instead emits a deprecation
warning for those cases, and makes them work the same way they
did in Python 3.5.
This patch also improves the related class machinery documentation
to cover these details and to include more reader-friendly
cross-references and index entries.
* BUILD_TUPLE_UNPACK and BUILD_MAP_UNPACK_WITH_CALL no longer generated with
single tuple or dict.
* Restored more informative error messages for incorrect var-positional and
var-keyword arguments.
* Removed code duplications in _PyEval_EvalCodeWithName().
* Removed redundant runtime checks and parameters in _PyStack_AsDict().
* Added a workaround and enabled previously disabled test in test_traceback.
* Removed dead code from the dis module.
The __class__ cell used by zero-argument super() is now initialized
from type.__new__ rather than __build_class__, so class methods
relying on that will now work correctly when called from metaclass
methods during class creation.
Patch by Martin Teichmann.
Issue #27213: Rework CALL_FUNCTION* opcodes to produce shorter and more
efficient bytecode:
* CALL_FUNCTION now only accepts position arguments
* CALL_FUNCTION_KW accepts position arguments and keyword arguments, but keys
of keyword arguments are packed into a constant tuple.
* CALL_FUNCTION_EX is the most generic, it expects a tuple and a dict for
positional and keyword arguments.
CALL_FUNCTION_VAR and CALL_FUNCTION_VAR_KW opcodes have been removed.
2 tests of test_traceback are currently broken: skip test, the issue #28050 was
created to track the issue.
Patch by Demur Rumed, design by Serhiy Storchaka, reviewed by Serhiy Storchaka
and Victor Stinner.
In practice, bytecode instruction arguments are unsigned. Update the assertion
to make it more explicit that argument must be greater or equal than 0.
Rewrite also the comment.
The compile ignores constant statements and emit a SyntaxWarning warning.
Don't emit the warning for string statement because triple quoted string is a
common syntax for multiline comments.
Don't emit the warning on ellipis neither: 'def f(): ...' is a legit syntax for
abstract functions.
Changes:
* test_ast: ignore SyntaxWarning when compiling test statements. Modify
test_load_const() to use assignment expressions rather than constant
expression.
* test_code: add more kinds of constant statements, ignore SyntaxWarning when
testing that the compiler removes constant statements.
* test_grammar: ignore SyntaxWarning on the statement "1"
Victor Stinner
Eric V. Smith
Pablo Galindo
Simeon
Zackery Spytz
Guido van Rossum
Serhiy Storchaka
Emily Morehouse
Ivan Levkivskyi
INADA Naoki
Ammar Askar
Benjamin Peterson
Zsolt Dollenstein
Mark Shannon
Nick Coghlan
Yury Selivanov
Barry Warsaw
Stefan Krah
Matthieu Dartiailh
Guido van Rossum
Victor Stinner
Ned Deily