# PEG grammar for Python @trailer ''' void * _PyPegen_parse(Parser *p) { // Initialize keywords p->keywords = reserved_keywords; p->n_keyword_lists = n_keyword_lists; p->soft_keywords = soft_keywords; // 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_func_type_input) { result = func_type_rule(p); } else if (p->start_rule == Py_fstring_input) { result = fstring_rule(p); } return result; } ''' # ========================= START OF THE GRAMMAR ========================= # General grammatical elements and rules: # # * Strings with double quotes (") denote SOFT KEYWORDS # * Strings with single quotes (') denote KEYWORDS # * Upper case names (NAME) denote tokens in the Grammar/Tokens file # * Rule names starting with "invalid_" are used for specialized syntax errors # - These rules are NOT used in the first pass of the parser. # - Only if the first pass fails to parse, a second pass including the invalid # rules will be executed. # - If the parser fails in the second phase with a generic syntax error, the # location of the generic failure of the first pass will be used (this avoids # reporting incorrect locations due to the invalid rules). # - The order of the alternatives involving invalid rules matter # (like any rule in PEG). # # Grammar Syntax (see PEP 617 for more information): # # rule_name: expression # Optionally, a type can be included right after the rule name, which # specifies the return type of the C or Python function corresponding to the # rule: # rule_name[return_type]: expression # If the return type is omitted, then a void * is returned in C and an Any in # Python. # e1 e2 # Match e1, then match e2. # e1 | e2 # Match e1 or e2. # The first alternative can also appear on the line after the rule name for # formatting purposes. In that case, a | must be used before the first # alternative, like so: # rule_name[return_type]: # | first_alt # | second_alt # ( e ) # Match e (allows also to use other operators in the group like '(e)*') # [ e ] or e? # Optionally match e. # e* # Match zero or more occurrences of e. # e+ # Match one or more occurrences of e. # s.e+ # Match one or more occurrences of e, separated by s. The generated parse tree # does not include the separator. This is otherwise identical to (e (s e)*). # &e # Succeed if e can be parsed, without consuming any input. # !e # Fail if e can be parsed, without consuming any input. # ~ # Commit to the current alternative, even if it fails to parse. # # STARTING RULES # ============== file[mod_ty]: a=[statements] ENDMARKER { _PyPegen_make_module(p, a) } interactive[mod_ty]: a=statement_newline { _PyAST_Interactive(a, p->arena) } eval[mod_ty]: a=expressions NEWLINE* ENDMARKER { _PyAST_Expression(a, p->arena) } func_type[mod_ty]: '(' a=[type_expressions] ')' '->' b=expression NEWLINE* ENDMARKER { _PyAST_FunctionType(a, b, p->arena) } fstring[expr_ty]: star_expressions # GENERAL STATEMENTS # ================== statements[asdl_stmt_seq*]: a=statement+ { (asdl_stmt_seq*)_PyPegen_seq_flatten(p, a) } statement[asdl_stmt_seq*]: a=compound_stmt { (asdl_stmt_seq*)_PyPegen_singleton_seq(p, a) } | a[asdl_stmt_seq*]=simple_stmts { a } statement_newline[asdl_stmt_seq*]: | a=compound_stmt NEWLINE { (asdl_stmt_seq*)_PyPegen_singleton_seq(p, a) } | simple_stmts | NEWLINE { (asdl_stmt_seq*)_PyPegen_singleton_seq(p, CHECK(stmt_ty, _PyAST_Pass(EXTRA))) } | ENDMARKER { _PyPegen_interactive_exit(p) } simple_stmts[asdl_stmt_seq*]: | a=simple_stmt !';' NEWLINE { (asdl_stmt_seq*)_PyPegen_singleton_seq(p, a) } # Not needed, there for speedup | a[asdl_stmt_seq*]=';'.simple_stmt+ [';'] NEWLINE { a } # NOTE: assignment MUST precede expression, else parsing a simple assignment # will throw a SyntaxError. simple_stmt[stmt_ty] (memo): | assignment | &"type" type_alias | e=star_expressions { _PyAST_Expr(e, EXTRA) } | &'return' return_stmt | &('import' | 'from') import_stmt | &'raise' raise_stmt | 'pass' { _PyAST_Pass(EXTRA) } | &'del' del_stmt | &'yield' yield_stmt | &'assert' assert_stmt | 'break' { _PyAST_Break(EXTRA) } | 'continue' { _PyAST_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 | match_stmt # SIMPLE STATEMENTS # ================= # NOTE: annotated_rhs may start with 'yield'; yield_expr must start with 'yield' assignment[stmt_ty]: | a=NAME ':' b=expression c=['=' d=annotated_rhs { d }] { CHECK_VERSION( stmt_ty, 6, "Variable annotation syntax is", _PyAST_AnnAssign(CHECK(expr_ty, _PyPegen_set_expr_context(p, a, Store)), b, c, 1, EXTRA) ) } | a=('(' b=single_target ')' { b } | single_subscript_attribute_target) ':' b=expression c=['=' d=annotated_rhs { d }] { CHECK_VERSION(stmt_ty, 6, "Variable annotations syntax is", _PyAST_AnnAssign(a, b, c, 0, EXTRA)) } | a[asdl_expr_seq*]=(z=star_targets '=' { z })+ b=(yield_expr | star_expressions) !'=' tc=[TYPE_COMMENT] { _PyAST_Assign(a, b, NEW_TYPE_COMMENT(p, tc), EXTRA) } | a=single_target b=augassign ~ c=(yield_expr | star_expressions) { _PyAST_AugAssign(a, b->kind, c, EXTRA) } | invalid_assignment annotated_rhs[expr_ty]: yield_expr | star_expressions augassign[AugOperator*]: | '+=' { _PyPegen_augoperator(p, Add) } | '-=' { _PyPegen_augoperator(p, Sub) } | '*=' { _PyPegen_augoperator(p, Mult) } | '@=' { CHECK_VERSION(AugOperator*, 5, "The '@' operator is", _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) } return_stmt[stmt_ty]: | 'return' a=[star_expressions] { _PyAST_Return(a, EXTRA) } raise_stmt[stmt_ty]: | 'raise' a=expression b=['from' z=expression { z }] { _PyAST_Raise(a, b, EXTRA) } | 'raise' { _PyAST_Raise(NULL, NULL, EXTRA) } global_stmt[stmt_ty]: 'global' a[asdl_expr_seq*]=','.NAME+ { _PyAST_Global(CHECK(asdl_identifier_seq*, _PyPegen_map_names_to_ids(p, a)), EXTRA) } nonlocal_stmt[stmt_ty]: 'nonlocal' a[asdl_expr_seq*]=','.NAME+ { _PyAST_Nonlocal(CHECK(asdl_identifier_seq*, _PyPegen_map_names_to_ids(p, a)), EXTRA) } del_stmt[stmt_ty]: | 'del' a=del_targets &(';' | NEWLINE) { _PyAST_Delete(a, EXTRA) } | invalid_del_stmt yield_stmt[stmt_ty]: y=yield_expr { _PyAST_Expr(y, EXTRA) } assert_stmt[stmt_ty]: 'assert' a=expression b=[',' z=expression { z }] { _PyAST_Assert(a, b, EXTRA) } import_stmt[stmt_ty]: | invalid_import | import_name | import_from # Import statements # ----------------- import_name[stmt_ty]: 'import' a=dotted_as_names { _PyAST_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 { _PyAST_ImportFrom(b->v.Name.id, c, _PyPegen_seq_count_dots(a), EXTRA) } | 'from' a=('.' | '...')+ 'import' b=import_from_targets { _PyAST_ImportFrom(NULL, b, _PyPegen_seq_count_dots(a), EXTRA) } import_from_targets[asdl_alias_seq*]: | '(' a=import_from_as_names [','] ')' { a } | import_from_as_names !',' | '*' { (asdl_alias_seq*)_PyPegen_singleton_seq(p, CHECK(alias_ty, _PyPegen_alias_for_star(p, EXTRA))) } | invalid_import_from_targets import_from_as_names[asdl_alias_seq*]: | a[asdl_alias_seq*]=','.import_from_as_name+ { a } import_from_as_name[alias_ty]: | a=NAME b=['as' z=NAME { z }] { _PyAST_alias(a->v.Name.id, (b) ? ((expr_ty) b)->v.Name.id : NULL, EXTRA) } dotted_as_names[asdl_alias_seq*]: | a[asdl_alias_seq*]=','.dotted_as_name+ { a } dotted_as_name[alias_ty]: | a=dotted_name b=['as' z=NAME { z }] { _PyAST_alias(a->v.Name.id, (b) ? ((expr_ty) b)->v.Name.id : NULL, EXTRA) } dotted_name[expr_ty]: | a=dotted_name '.' b=NAME { _PyPegen_join_names_with_dot(p, a, b) } | NAME # COMPOUND STATEMENTS # =================== # Common elements # --------------- block[asdl_stmt_seq*] (memo): | NEWLINE INDENT a=statements DEDENT { a } | simple_stmts | invalid_block decorators[asdl_expr_seq*]: a[asdl_expr_seq*]=('@' f=named_expression NEWLINE { f })+ { a } # Class definitions # ----------------- 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]: | invalid_class_def_raw | 'class' a=NAME t=[type_params] b=['(' z=[arguments] ')' { z }] ':' c=block { _PyAST_ClassDef(a->v.Name.id, (b) ? ((expr_ty) b)->v.Call.args : NULL, (b) ? ((expr_ty) b)->v.Call.keywords : NULL, c, NULL, t, EXTRA) } # Function definitions # -------------------- 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]: | invalid_def_raw | 'def' n=NAME t=[type_params] &&'(' params=[params] ')' a=['->' z=expression { z }] &&':' tc=[func_type_comment] b=block { _PyAST_FunctionDef(n->v.Name.id, (params) ? params : CHECK(arguments_ty, _PyPegen_empty_arguments(p)), b, NULL, a, NEW_TYPE_COMMENT(p, tc), t, EXTRA) } | ASYNC 'def' n=NAME t=[type_params] &&'(' params=[params] ')' a=['->' z=expression { z }] &&':' tc=[func_type_comment] b=block { CHECK_VERSION( stmt_ty, 5, "Async functions are", _PyAST_AsyncFunctionDef(n->v.Name.id, (params) ? params : CHECK(arguments_ty, _PyPegen_empty_arguments(p)), b, NULL, a, NEW_TYPE_COMMENT(p, tc), t, EXTRA) ) } # Function parameters # ------------------- params[arguments_ty]: | invalid_parameters | parameters parameters[arguments_ty]: | a=slash_no_default b[asdl_arg_seq*]=param_no_default* c=param_with_default* d=[star_etc] { CHECK_VERSION(arguments_ty, 8, "Positional-only parameters are", _PyPegen_make_arguments(p, a, NULL, b, c, d)) } | a=slash_with_default b=param_with_default* c=[star_etc] { CHECK_VERSION(arguments_ty, 8, "Positional-only parameters are", _PyPegen_make_arguments(p, NULL, a, NULL, b, c)) } | a[asdl_arg_seq*]=param_no_default+ b=param_with_default* c=[star_etc] { _PyPegen_make_arguments(p, NULL, NULL, a, b, c) } | a=param_with_default+ b=[star_etc] { _PyPegen_make_arguments(p, NULL, NULL, NULL, a, b)} | a=star_etc { _PyPegen_make_arguments(p, NULL, NULL, NULL, NULL, a) } # Some duplication here because we can't write (',' | &')'), # which is because we don't support empty alternatives (yet). slash_no_default[asdl_arg_seq*]: | a[asdl_arg_seq*]=param_no_default+ '/' ',' { a } | a[asdl_arg_seq*]=param_no_default+ '/' &')' { a } slash_with_default[SlashWithDefault*]: | a=param_no_default* b=param_with_default+ '/' ',' { _PyPegen_slash_with_default(p, (asdl_arg_seq *)a, b) } | a=param_no_default* b=param_with_default+ '/' &')' { _PyPegen_slash_with_default(p, (asdl_arg_seq *)a, b) } star_etc[StarEtc*]: | invalid_star_etc | '*' a=param_no_default b=param_maybe_default* c=[kwds] { _PyPegen_star_etc(p, a, b, c) } | '*' a=param_no_default_star_annotation b=param_maybe_default* c=[kwds] { _PyPegen_star_etc(p, a, b, c) } | '*' ',' b=param_maybe_default+ c=[kwds] { _PyPegen_star_etc(p, NULL, b, c) } | a=kwds { _PyPegen_star_etc(p, NULL, NULL, a) } kwds[arg_ty]: | invalid_kwds | '**' a=param_no_default { a } # One parameter. This *includes* a following comma and type comment. # # There are three styles: # - No default # - With default # - Maybe with default # # There are two alternative forms of each, to deal with type comments: # - Ends in a comma followed by an optional type comment # - No comma, optional type comment, must be followed by close paren # The latter form is for a final parameter without trailing comma. # param_no_default[arg_ty]: | a=param ',' tc=TYPE_COMMENT? { _PyPegen_add_type_comment_to_arg(p, a, tc) } | a=param tc=TYPE_COMMENT? &')' { _PyPegen_add_type_comment_to_arg(p, a, tc) } param_no_default_star_annotation[arg_ty]: | a=param_star_annotation ',' tc=TYPE_COMMENT? { _PyPegen_add_type_comment_to_arg(p, a, tc) } | a=param_star_annotation tc=TYPE_COMMENT? &')' { _PyPegen_add_type_comment_to_arg(p, a, tc) } param_with_default[NameDefaultPair*]: | a=param c=default ',' tc=TYPE_COMMENT? { _PyPegen_name_default_pair(p, a, c, tc) } | a=param c=default tc=TYPE_COMMENT? &')' { _PyPegen_name_default_pair(p, a, c, tc) } param_maybe_default[NameDefaultPair*]: | a=param c=default? ',' tc=TYPE_COMMENT? { _PyPegen_name_default_pair(p, a, c, tc) } | a=param c=default? tc=TYPE_COMMENT? &')' { _PyPegen_name_default_pair(p, a, c, tc) } param[arg_ty]: a=NAME b=annotation? { _PyAST_arg(a->v.Name.id, b, NULL, EXTRA) } param_star_annotation[arg_ty]: a=NAME b=star_annotation { _PyAST_arg(a->v.Name.id, b, NULL, EXTRA) } annotation[expr_ty]: ':' a=expression { a } star_annotation[expr_ty]: ':' a=star_expression { a } default[expr_ty]: '=' a=expression { a } | invalid_default # If statement # ------------ if_stmt[stmt_ty]: | invalid_if_stmt | 'if' a=named_expression ':' b=block c=elif_stmt { _PyAST_If(a, b, CHECK(asdl_stmt_seq*, _PyPegen_singleton_seq(p, c)), EXTRA) } | 'if' a=named_expression ':' b=block c=[else_block] { _PyAST_If(a, b, c, EXTRA) } elif_stmt[stmt_ty]: | invalid_elif_stmt | 'elif' a=named_expression ':' b=block c=elif_stmt { _PyAST_If(a, b, CHECK(asdl_stmt_seq*, _PyPegen_singleton_seq(p, c)), EXTRA) } | 'elif' a=named_expression ':' b=block c=[else_block] { _PyAST_If(a, b, c, EXTRA) } else_block[asdl_stmt_seq*]: | invalid_else_stmt | 'else' &&':' b=block { b } # While statement # --------------- while_stmt[stmt_ty]: | invalid_while_stmt | 'while' a=named_expression ':' b=block c=[else_block] { _PyAST_While(a, b, c, EXTRA) } # For statement # ------------- for_stmt[stmt_ty]: | invalid_for_stmt | 'for' t=star_targets 'in' ~ ex=star_expressions ':' tc=[TYPE_COMMENT] b=block el=[else_block] { _PyAST_For(t, ex, b, el, NEW_TYPE_COMMENT(p, tc), EXTRA) } | ASYNC 'for' t=star_targets 'in' ~ ex=star_expressions ':' tc=[TYPE_COMMENT] b=block el=[else_block] { CHECK_VERSION(stmt_ty, 5, "Async for loops are", _PyAST_AsyncFor(t, ex, b, el, NEW_TYPE_COMMENT(p, tc), EXTRA)) } | invalid_for_target # With statement # -------------- with_stmt[stmt_ty]: | invalid_with_stmt_indent | 'with' '(' a[asdl_withitem_seq*]=','.with_item+ ','? ')' ':' b=block { CHECK_VERSION(stmt_ty, 9, "Parenthesized context managers are", _PyAST_With(a, b, NULL, EXTRA)) } | 'with' a[asdl_withitem_seq*]=','.with_item+ ':' tc=[TYPE_COMMENT] b=block { _PyAST_With(a, b, NEW_TYPE_COMMENT(p, tc), EXTRA) } | ASYNC 'with' '(' a[asdl_withitem_seq*]=','.with_item+ ','? ')' ':' b=block { CHECK_VERSION(stmt_ty, 5, "Async with statements are", _PyAST_AsyncWith(a, b, NULL, EXTRA)) } | ASYNC 'with' a[asdl_withitem_seq*]=','.with_item+ ':' tc=[TYPE_COMMENT] b=block { CHECK_VERSION(stmt_ty, 5, "Async with statements are", _PyAST_AsyncWith(a, b, NEW_TYPE_COMMENT(p, tc), EXTRA)) } | invalid_with_stmt with_item[withitem_ty]: | e=expression 'as' t=star_target &(',' | ')' | ':') { _PyAST_withitem(e, t, p->arena) } | invalid_with_item | e=expression { _PyAST_withitem(e, NULL, p->arena) } # Try statement # ------------- try_stmt[stmt_ty]: | invalid_try_stmt | 'try' &&':' b=block f=finally_block { _PyAST_Try(b, NULL, NULL, f, EXTRA) } | 'try' &&':' b=block ex[asdl_excepthandler_seq*]=except_block+ el=[else_block] f=[finally_block] { _PyAST_Try(b, ex, el, f, EXTRA) } | 'try' &&':' b=block ex[asdl_excepthandler_seq*]=except_star_block+ el=[else_block] f=[finally_block] { CHECK_VERSION(stmt_ty, 11, "Exception groups are", _PyAST_TryStar(b, ex, el, f, EXTRA)) } # Except statement # ---------------- except_block[excepthandler_ty]: | invalid_except_stmt_indent | 'except' e=expression t=['as' z=NAME { z }] ':' b=block { _PyAST_ExceptHandler(e, (t) ? ((expr_ty) t)->v.Name.id : NULL, b, EXTRA) } | 'except' ':' b=block { _PyAST_ExceptHandler(NULL, NULL, b, EXTRA) } | invalid_except_stmt except_star_block[excepthandler_ty]: | invalid_except_star_stmt_indent | 'except' '*' e=expression t=['as' z=NAME { z }] ':' b=block { _PyAST_ExceptHandler(e, (t) ? ((expr_ty) t)->v.Name.id : NULL, b, EXTRA) } | invalid_except_stmt finally_block[asdl_stmt_seq*]: | invalid_finally_stmt | 'finally' &&':' a=block { a } # Match statement # --------------- match_stmt[stmt_ty]: | "match" subject=subject_expr ':' NEWLINE INDENT cases[asdl_match_case_seq*]=case_block+ DEDENT { CHECK_VERSION(stmt_ty, 10, "Pattern matching is", _PyAST_Match(subject, cases, EXTRA)) } | invalid_match_stmt subject_expr[expr_ty]: | value=star_named_expression ',' values=star_named_expressions? { _PyAST_Tuple(CHECK(asdl_expr_seq*, _PyPegen_seq_insert_in_front(p, value, values)), Load, EXTRA) } | named_expression case_block[match_case_ty]: | invalid_case_block | "case" pattern=patterns guard=guard? ':' body=block { _PyAST_match_case(pattern, guard, body, p->arena) } guard[expr_ty]: 'if' guard=named_expression { guard } patterns[pattern_ty]: | patterns[asdl_pattern_seq*]=open_sequence_pattern { _PyAST_MatchSequence(patterns, EXTRA) } | pattern pattern[pattern_ty]: | as_pattern | or_pattern as_pattern[pattern_ty]: | pattern=or_pattern 'as' target=pattern_capture_target { _PyAST_MatchAs(pattern, target->v.Name.id, EXTRA) } | invalid_as_pattern or_pattern[pattern_ty]: | patterns[asdl_pattern_seq*]='|'.closed_pattern+ { asdl_seq_LEN(patterns) == 1 ? asdl_seq_GET(patterns, 0) : _PyAST_MatchOr(patterns, EXTRA) } closed_pattern[pattern_ty] (memo): | literal_pattern | capture_pattern | wildcard_pattern | value_pattern | group_pattern | sequence_pattern | mapping_pattern | class_pattern # Literal patterns are used for equality and identity constraints literal_pattern[pattern_ty]: | value=signed_number !('+' | '-') { _PyAST_MatchValue(value, EXTRA) } | value=complex_number { _PyAST_MatchValue(value, EXTRA) } | value=strings { _PyAST_MatchValue(value, EXTRA) } | 'None' { _PyAST_MatchSingleton(Py_None, EXTRA) } | 'True' { _PyAST_MatchSingleton(Py_True, EXTRA) } | 'False' { _PyAST_MatchSingleton(Py_False, EXTRA) } # Literal expressions are used to restrict permitted mapping pattern keys literal_expr[expr_ty]: | signed_number !('+' | '-') | complex_number | strings | 'None' { _PyAST_Constant(Py_None, NULL, EXTRA) } | 'True' { _PyAST_Constant(Py_True, NULL, EXTRA) } | 'False' { _PyAST_Constant(Py_False, NULL, EXTRA) } complex_number[expr_ty]: | real=signed_real_number '+' imag=imaginary_number { _PyAST_BinOp(real, Add, imag, EXTRA) } | real=signed_real_number '-' imag=imaginary_number { _PyAST_BinOp(real, Sub, imag, EXTRA) } signed_number[expr_ty]: | NUMBER | '-' number=NUMBER { _PyAST_UnaryOp(USub, number, EXTRA) } signed_real_number[expr_ty]: | real_number | '-' real=real_number { _PyAST_UnaryOp(USub, real, EXTRA) } real_number[expr_ty]: | real=NUMBER { _PyPegen_ensure_real(p, real) } imaginary_number[expr_ty]: | imag=NUMBER { _PyPegen_ensure_imaginary(p, imag) } capture_pattern[pattern_ty]: | target=pattern_capture_target { _PyAST_MatchAs(NULL, target->v.Name.id, EXTRA) } pattern_capture_target[expr_ty]: | !"_" name=NAME !('.' | '(' | '=') { _PyPegen_set_expr_context(p, name, Store) } wildcard_pattern[pattern_ty]: | "_" { _PyAST_MatchAs(NULL, NULL, EXTRA) } value_pattern[pattern_ty]: | attr=attr !('.' | '(' | '=') { _PyAST_MatchValue(attr, EXTRA) } attr[expr_ty]: | value=name_or_attr '.' attr=NAME { _PyAST_Attribute(value, attr->v.Name.id, Load, EXTRA) } name_or_attr[expr_ty]: | attr | NAME group_pattern[pattern_ty]: | '(' pattern=pattern ')' { pattern } sequence_pattern[pattern_ty]: | '[' patterns=maybe_sequence_pattern? ']' { _PyAST_MatchSequence(patterns, EXTRA) } | '(' patterns=open_sequence_pattern? ')' { _PyAST_MatchSequence(patterns, EXTRA) } open_sequence_pattern[asdl_seq*]: | pattern=maybe_star_pattern ',' patterns=maybe_sequence_pattern? { _PyPegen_seq_insert_in_front(p, pattern, patterns) } maybe_sequence_pattern[asdl_seq*]: | patterns=','.maybe_star_pattern+ ','? { patterns } maybe_star_pattern[pattern_ty]: | star_pattern | pattern star_pattern[pattern_ty] (memo): | '*' target=pattern_capture_target { _PyAST_MatchStar(target->v.Name.id, EXTRA) } | '*' wildcard_pattern { _PyAST_MatchStar(NULL, EXTRA) } mapping_pattern[pattern_ty]: | '{' '}' { _PyAST_MatchMapping(NULL, NULL, NULL, EXTRA) } | '{' rest=double_star_pattern ','? '}' { _PyAST_MatchMapping(NULL, NULL, rest->v.Name.id, EXTRA) } | '{' items=items_pattern ',' rest=double_star_pattern ','? '}' { _PyAST_MatchMapping( CHECK(asdl_expr_seq*, _PyPegen_get_pattern_keys(p, items)), CHECK(asdl_pattern_seq*, _PyPegen_get_patterns(p, items)), rest->v.Name.id, EXTRA) } | '{' items=items_pattern ','? '}' { _PyAST_MatchMapping( CHECK(asdl_expr_seq*, _PyPegen_get_pattern_keys(p, items)), CHECK(asdl_pattern_seq*, _PyPegen_get_patterns(p, items)), NULL, EXTRA) } items_pattern[asdl_seq*]: | ','.key_value_pattern+ key_value_pattern[KeyPatternPair*]: | key=(literal_expr | attr) ':' pattern=pattern { _PyPegen_key_pattern_pair(p, key, pattern) } double_star_pattern[expr_ty]: | '**' target=pattern_capture_target { target } class_pattern[pattern_ty]: | cls=name_or_attr '(' ')' { _PyAST_MatchClass(cls, NULL, NULL, NULL, EXTRA) } | cls=name_or_attr '(' patterns=positional_patterns ','? ')' { _PyAST_MatchClass(cls, patterns, NULL, NULL, EXTRA) } | cls=name_or_attr '(' keywords=keyword_patterns ','? ')' { _PyAST_MatchClass( cls, NULL, CHECK(asdl_identifier_seq*, _PyPegen_map_names_to_ids(p, CHECK(asdl_expr_seq*, _PyPegen_get_pattern_keys(p, keywords)))), CHECK(asdl_pattern_seq*, _PyPegen_get_patterns(p, keywords)), EXTRA) } | cls=name_or_attr '(' patterns=positional_patterns ',' keywords=keyword_patterns ','? ')' { _PyAST_MatchClass( cls, patterns, CHECK(asdl_identifier_seq*, _PyPegen_map_names_to_ids(p, CHECK(asdl_expr_seq*, _PyPegen_get_pattern_keys(p, keywords)))), CHECK(asdl_pattern_seq*, _PyPegen_get_patterns(p, keywords)), EXTRA) } | invalid_class_pattern positional_patterns[asdl_pattern_seq*]: | args[asdl_pattern_seq*]=','.pattern+ { args } keyword_patterns[asdl_seq*]: | ','.keyword_pattern+ keyword_pattern[KeyPatternPair*]: | arg=NAME '=' value=pattern { _PyPegen_key_pattern_pair(p, arg, value) } # Type statement # --------------- type_alias[stmt_ty]: | "type" n=NAME t=[type_params] '=' b=expression { CHECK_VERSION(stmt_ty, 12, "Type statement is", _PyAST_TypeAlias(CHECK(expr_ty, _PyPegen_set_expr_context(p, n, Store)), t, b, EXTRA)) } # Type parameter declaration # -------------------------- type_params[asdl_type_param_seq*]: '[' t=type_param_seq ']' { CHECK_VERSION(asdl_type_param_seq *, 12, "Type parameter lists are", t) } type_param_seq[asdl_type_param_seq*]: a[asdl_type_param_seq*]=','.type_param+ [','] { a } type_param[type_param_ty] (memo): | a=NAME b=[type_param_bound] { _PyAST_TypeVar(a->v.Name.id, b, EXTRA) } | '*' a=NAME colon=":" e=expression { RAISE_SYNTAX_ERROR_STARTING_FROM(colon, e->kind == Tuple_kind ? "cannot use constraints with TypeVarTuple" : "cannot use bound with TypeVarTuple") } | '*' a=NAME { _PyAST_TypeVarTuple(a->v.Name.id, EXTRA) } | '**' a=NAME colon=":" e=expression { RAISE_SYNTAX_ERROR_STARTING_FROM(colon, e->kind == Tuple_kind ? "cannot use constraints with ParamSpec" : "cannot use bound with ParamSpec") } | '**' a=NAME { _PyAST_ParamSpec(a->v.Name.id, EXTRA) } type_param_bound[expr_ty]: ":" e=expression { e } # EXPRESSIONS # ----------- expressions[expr_ty]: | a=expression b=(',' c=expression { c })+ [','] { _PyAST_Tuple(CHECK(asdl_expr_seq*, _PyPegen_seq_insert_in_front(p, a, b)), Load, EXTRA) } | a=expression ',' { _PyAST_Tuple(CHECK(asdl_expr_seq*, _PyPegen_singleton_seq(p, a)), Load, EXTRA) } | expression expression[expr_ty] (memo): | invalid_expression | invalid_legacy_expression | a=disjunction 'if' b=disjunction 'else' c=expression { _PyAST_IfExp(b, a, c, EXTRA) } | disjunction | lambdef yield_expr[expr_ty]: | 'yield' 'from' a=expression { _PyAST_YieldFrom(a, EXTRA) } | 'yield' a=[star_expressions] { _PyAST_Yield(a, EXTRA) } star_expressions[expr_ty]: | a=star_expression b=(',' c=star_expression { c })+ [','] { _PyAST_Tuple(CHECK(asdl_expr_seq*, _PyPegen_seq_insert_in_front(p, a, b)), Load, EXTRA) } | a=star_expression ',' { _PyAST_Tuple(CHECK(asdl_expr_seq*, _PyPegen_singleton_seq(p, a)), Load, EXTRA) } | star_expression star_expression[expr_ty] (memo): | '*' a=bitwise_or { _PyAST_Starred(a, Load, EXTRA) } | expression star_named_expressions[asdl_expr_seq*]: a[asdl_expr_seq*]=','.star_named_expression+ [','] { a } star_named_expression[expr_ty]: | '*' a=bitwise_or { _PyAST_Starred(a, Load, EXTRA) } | named_expression assignment_expression[expr_ty]: | a=NAME ':=' ~ b=expression { CHECK_VERSION(expr_ty, 8, "Assignment expressions are", _PyAST_NamedExpr(CHECK(expr_ty, _PyPegen_set_expr_context(p, a, Store)), b, EXTRA)) } named_expression[expr_ty]: | assignment_expression | invalid_named_expression | expression !':=' disjunction[expr_ty] (memo): | a=conjunction b=('or' c=conjunction { c })+ { _PyAST_BoolOp( Or, CHECK(asdl_expr_seq*, _PyPegen_seq_insert_in_front(p, a, b)), EXTRA) } | conjunction conjunction[expr_ty] (memo): | a=inversion b=('and' c=inversion { c })+ { _PyAST_BoolOp( And, CHECK(asdl_expr_seq*, _PyPegen_seq_insert_in_front(p, a, b)), EXTRA) } | inversion inversion[expr_ty] (memo): | 'not' a=inversion { _PyAST_UnaryOp(Not, a, EXTRA) } | comparison # Comparison operators # -------------------- comparison[expr_ty]: | a=bitwise_or b=compare_op_bitwise_or_pair+ { _PyAST_Compare( a, CHECK(asdl_int_seq*, _PyPegen_get_cmpops(p, b)), CHECK(asdl_expr_seq*, _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*]: | (tok='!=' { _PyPegen_check_barry_as_flufl(p, tok) ? NULL : tok}) 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 operators # ----------------- bitwise_or[expr_ty]: | a=bitwise_or '|' b=bitwise_xor { _PyAST_BinOp(a, BitOr, b, EXTRA) } | bitwise_xor bitwise_xor[expr_ty]: | a=bitwise_xor '^' b=bitwise_and { _PyAST_BinOp(a, BitXor, b, EXTRA) } | bitwise_and bitwise_and[expr_ty]: | a=bitwise_and '&' b=shift_expr { _PyAST_BinOp(a, BitAnd, b, EXTRA) } | shift_expr shift_expr[expr_ty]: | a=shift_expr '<<' b=sum { _PyAST_BinOp(a, LShift, b, EXTRA) } | a=shift_expr '>>' b=sum { _PyAST_BinOp(a, RShift, b, EXTRA) } | sum # Arithmetic operators # -------------------- sum[expr_ty]: | a=sum '+' b=term { _PyAST_BinOp(a, Add, b, EXTRA) } | a=sum '-' b=term { _PyAST_BinOp(a, Sub, b, EXTRA) } | term term[expr_ty]: | a=term '*' b=factor { _PyAST_BinOp(a, Mult, b, EXTRA) } | a=term '/' b=factor { _PyAST_BinOp(a, Div, b, EXTRA) } | a=term '//' b=factor { _PyAST_BinOp(a, FloorDiv, b, EXTRA) } | a=term '%' b=factor { _PyAST_BinOp(a, Mod, b, EXTRA) } | a=term '@' b=factor { CHECK_VERSION(expr_ty, 5, "The '@' operator is", _PyAST_BinOp(a, MatMult, b, EXTRA)) } | factor factor[expr_ty] (memo): | '+' a=factor { _PyAST_UnaryOp(UAdd, a, EXTRA) } | '-' a=factor { _PyAST_UnaryOp(USub, a, EXTRA) } | '~' a=factor { _PyAST_UnaryOp(Invert, a, EXTRA) } | power power[expr_ty]: | a=await_primary '**' b=factor { _PyAST_BinOp(a, Pow, b, EXTRA) } | await_primary # Primary elements # ---------------- # Primary elements are things like "obj.something.something", "obj[something]", "obj(something)", "obj" ... await_primary[expr_ty] (memo): | AWAIT a=primary { CHECK_VERSION(expr_ty, 5, "Await expressions are", _PyAST_Await(a, EXTRA)) } | primary primary[expr_ty]: | a=primary '.' b=NAME { _PyAST_Attribute(a, b->v.Name.id, Load, EXTRA) } | a=primary b=genexp { _PyAST_Call(a, CHECK(asdl_expr_seq*, (asdl_expr_seq*)_PyPegen_singleton_seq(p, b)), NULL, EXTRA) } | a=primary '(' b=[arguments] ')' { _PyAST_Call(a, (b) ? ((expr_ty) b)->v.Call.args : NULL, (b) ? ((expr_ty) b)->v.Call.keywords : NULL, EXTRA) } | a=primary '[' b=slices ']' { _PyAST_Subscript(a, b, Load, EXTRA) } | atom slices[expr_ty]: | a=slice !',' { a } | a[asdl_expr_seq*]=','.(slice | starred_expression)+ [','] { _PyAST_Tuple(a, Load, EXTRA) } slice[expr_ty]: | a=[expression] ':' b=[expression] c=[':' d=[expression] { d }] { _PyAST_Slice(a, b, c, EXTRA) } | a=named_expression { a } atom[expr_ty]: | NAME | 'True' { _PyAST_Constant(Py_True, NULL, EXTRA) } | 'False' { _PyAST_Constant(Py_False, NULL, EXTRA) } | 'None' { _PyAST_Constant(Py_None, NULL, EXTRA) } | &(STRING|FSTRING_START) strings | NUMBER | &'(' (tuple | group | genexp) | &'[' (list | listcomp) | &'{' (dict | set | dictcomp | setcomp) | '...' { _PyAST_Constant(Py_Ellipsis, NULL, EXTRA) } group[expr_ty]: | '(' a=(yield_expr | named_expression) ')' { a } | invalid_group # Lambda functions # ---------------- lambdef[expr_ty]: | 'lambda' a=[lambda_params] ':' b=expression { _PyAST_Lambda((a) ? a : CHECK(arguments_ty, _PyPegen_empty_arguments(p)), b, EXTRA) } lambda_params[arguments_ty]: | invalid_lambda_parameters | lambda_parameters # lambda_parameters etc. duplicates parameters but without annotations # or type comments, and if there's no comma after a parameter, we expect # a colon, not a close parenthesis. (For more, see parameters above.) # lambda_parameters[arguments_ty]: | a=lambda_slash_no_default b[asdl_arg_seq*]=lambda_param_no_default* c=lambda_param_with_default* d=[lambda_star_etc] { CHECK_VERSION(arguments_ty, 8, "Positional-only parameters are", _PyPegen_make_arguments(p, a, NULL, b, c, d)) } | a=lambda_slash_with_default b=lambda_param_with_default* c=[lambda_star_etc] { CHECK_VERSION(arguments_ty, 8, "Positional-only parameters are", _PyPegen_make_arguments(p, NULL, a, NULL, b, c)) } | a[asdl_arg_seq*]=lambda_param_no_default+ b=lambda_param_with_default* c=[lambda_star_etc] { _PyPegen_make_arguments(p, NULL, NULL, a, b, c) } | a=lambda_param_with_default+ b=[lambda_star_etc] { _PyPegen_make_arguments(p, NULL, NULL, NULL, a, b)} | a=lambda_star_etc { _PyPegen_make_arguments(p, NULL, NULL, NULL, NULL, a) } lambda_slash_no_default[asdl_arg_seq*]: | a[asdl_arg_seq*]=lambda_param_no_default+ '/' ',' { a } | a[asdl_arg_seq*]=lambda_param_no_default+ '/' &':' { a } lambda_slash_with_default[SlashWithDefault*]: | a=lambda_param_no_default* b=lambda_param_with_default+ '/' ',' { _PyPegen_slash_with_default(p, (asdl_arg_seq *)a, b) } | a=lambda_param_no_default* b=lambda_param_with_default+ '/' &':' { _PyPegen_slash_with_default(p, (asdl_arg_seq *)a, b) } lambda_star_etc[StarEtc*]: | invalid_lambda_star_etc | '*' a=lambda_param_no_default b=lambda_param_maybe_default* c=[lambda_kwds] { _PyPegen_star_etc(p, a, b, c) } | '*' ',' b=lambda_param_maybe_default+ c=[lambda_kwds] { _PyPegen_star_etc(p, NULL, b, c) } | a=lambda_kwds { _PyPegen_star_etc(p, NULL, NULL, a) } lambda_kwds[arg_ty]: | invalid_lambda_kwds | '**' a=lambda_param_no_default { a } lambda_param_no_default[arg_ty]: | a=lambda_param ',' { a } | a=lambda_param &':' { a } lambda_param_with_default[NameDefaultPair*]: | a=lambda_param c=default ',' { _PyPegen_name_default_pair(p, a, c, NULL) } | a=lambda_param c=default &':' { _PyPegen_name_default_pair(p, a, c, NULL) } lambda_param_maybe_default[NameDefaultPair*]: | a=lambda_param c=default? ',' { _PyPegen_name_default_pair(p, a, c, NULL) } | a=lambda_param c=default? &':' { _PyPegen_name_default_pair(p, a, c, NULL) } lambda_param[arg_ty]: a=NAME { _PyAST_arg(a->v.Name.id, NULL, NULL, EXTRA) } # LITERALS # ======== fstring_middle[expr_ty]: | fstring_replacement_field | t=FSTRING_MIDDLE { _PyPegen_constant_from_token(p, t) } fstring_replacement_field[expr_ty]: | '{' a=(yield_expr | star_expressions) debug_expr="="? conversion=[fstring_conversion] format=[fstring_full_format_spec] rbrace='}' { _PyPegen_formatted_value(p, a, debug_expr, conversion, format, rbrace, EXTRA) } | invalid_replacement_field fstring_conversion[ResultTokenWithMetadata*]: | conv_token="!" conv=NAME { _PyPegen_check_fstring_conversion(p, conv_token, conv) } fstring_full_format_spec[ResultTokenWithMetadata*]: | colon=':' spec=fstring_format_spec* { _PyPegen_setup_full_format_spec(p, colon, (asdl_expr_seq *) spec, EXTRA) } fstring_format_spec[expr_ty]: | t=FSTRING_MIDDLE { _PyPegen_decoded_constant_from_token(p, t) } | fstring_replacement_field fstring[expr_ty]: | a=FSTRING_START b=fstring_middle* c=FSTRING_END { _PyPegen_joined_str(p, a, (asdl_expr_seq*)b, c) } string[expr_ty]: s[Token*]=STRING { _PyPegen_constant_from_string(p, s) } strings[expr_ty] (memo): a[asdl_expr_seq*]=(fstring|string)+ { _PyPegen_concatenate_strings(p, a, EXTRA) } list[expr_ty]: | '[' a=[star_named_expressions] ']' { _PyAST_List(a, Load, EXTRA) } tuple[expr_ty]: | '(' a=[y=star_named_expression ',' z=[star_named_expressions] { _PyPegen_seq_insert_in_front(p, y, z) } ] ')' { _PyAST_Tuple(a, Load, EXTRA) } set[expr_ty]: '{' a=star_named_expressions '}' { _PyAST_Set(a, EXTRA) } # Dicts # ----- dict[expr_ty]: | '{' a=[double_starred_kvpairs] '}' { _PyAST_Dict( CHECK(asdl_expr_seq*, _PyPegen_get_keys(p, a)), CHECK(asdl_expr_seq*, _PyPegen_get_values(p, a)), EXTRA) } | '{' invalid_double_starred_kvpairs '}' double_starred_kvpairs[asdl_seq*]: a=','.double_starred_kvpair+ [','] { a } double_starred_kvpair[KeyValuePair*]: | '**' a=bitwise_or { _PyPegen_key_value_pair(p, NULL, a) } | kvpair kvpair[KeyValuePair*]: a=expression ':' b=expression { _PyPegen_key_value_pair(p, a, b) } # Comprehensions & Generators # --------------------------- for_if_clauses[asdl_comprehension_seq*]: | a[asdl_comprehension_seq*]=for_if_clause+ { a } for_if_clause[comprehension_ty]: | ASYNC 'for' a=star_targets 'in' ~ b=disjunction c[asdl_expr_seq*]=('if' z=disjunction { z })* { CHECK_VERSION(comprehension_ty, 6, "Async comprehensions are", _PyAST_comprehension(a, b, c, 1, p->arena)) } | 'for' a=star_targets 'in' ~ b=disjunction c[asdl_expr_seq*]=('if' z=disjunction { z })* { _PyAST_comprehension(a, b, c, 0, p->arena) } | invalid_for_target listcomp[expr_ty]: | '[' a=named_expression b=for_if_clauses ']' { _PyAST_ListComp(a, b, EXTRA) } | invalid_comprehension setcomp[expr_ty]: | '{' a=named_expression b=for_if_clauses '}' { _PyAST_SetComp(a, b, EXTRA) } | invalid_comprehension genexp[expr_ty]: | '(' a=( assignment_expression | expression !':=') b=for_if_clauses ')' { _PyAST_GeneratorExp(a, b, EXTRA) } | invalid_comprehension dictcomp[expr_ty]: | '{' a=kvpair b=for_if_clauses '}' { _PyAST_DictComp(a->key, a->value, b, EXTRA) } | invalid_dict_comprehension # FUNCTION CALL ARGUMENTS # ======================= arguments[expr_ty] (memo): | a=args [','] &')' { a } | invalid_arguments args[expr_ty]: | a[asdl_expr_seq*]=','.(starred_expression | ( assignment_expression | expression !':=') !'=')+ b=[',' k=kwargs {k}] { _PyPegen_collect_call_seqs(p, a, b, EXTRA) } | a=kwargs { _PyAST_Call(_PyPegen_dummy_name(p), CHECK_NULL_ALLOWED(asdl_expr_seq*, _PyPegen_seq_extract_starred_exprs(p, a)), CHECK_NULL_ALLOWED(asdl_keyword_seq*, _PyPegen_seq_delete_starred_exprs(p, a)), 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]: | invalid_starred_expression | '*' a=expression { _PyAST_Starred(a, Load, EXTRA) } kwarg_or_starred[KeywordOrStarred*]: | invalid_kwarg | a=NAME '=' b=expression { _PyPegen_keyword_or_starred(p, CHECK(keyword_ty, _PyAST_keyword(a->v.Name.id, b, EXTRA)), 1) } | a=starred_expression { _PyPegen_keyword_or_starred(p, a, 0) } kwarg_or_double_starred[KeywordOrStarred*]: | invalid_kwarg | a=NAME '=' b=expression { _PyPegen_keyword_or_starred(p, CHECK(keyword_ty, _PyAST_keyword(a->v.Name.id, b, EXTRA)), 1) } | '**' a=expression { _PyPegen_keyword_or_starred(p, CHECK(keyword_ty, _PyAST_keyword(NULL, a, EXTRA)), 1) } # ASSIGNMENT TARGETS # ================== # Generic targets # --------------- # 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 })* [','] { _PyAST_Tuple(CHECK(asdl_expr_seq*, _PyPegen_seq_insert_in_front(p, a, b)), Store, EXTRA) } star_targets_list_seq[asdl_expr_seq*]: a[asdl_expr_seq*]=','.star_target+ [','] { a } star_targets_tuple_seq[asdl_expr_seq*]: | a=star_target b=(',' c=star_target { c })+ [','] { (asdl_expr_seq*) _PyPegen_seq_insert_in_front(p, a, b) } | a=star_target ',' { (asdl_expr_seq*) _PyPegen_singleton_seq(p, a) } star_target[expr_ty] (memo): | '*' a=(!'*' star_target) { _PyAST_Starred(CHECK(expr_ty, _PyPegen_set_expr_context(p, a, Store)), Store, EXTRA) } | target_with_star_atom target_with_star_atom[expr_ty] (memo): | a=t_primary '.' b=NAME !t_lookahead { _PyAST_Attribute(a, b->v.Name.id, Store, EXTRA) } | a=t_primary '[' b=slices ']' !t_lookahead { _PyAST_Subscript(a, b, Store, EXTRA) } | star_atom star_atom[expr_ty]: | a=NAME { _PyPegen_set_expr_context(p, a, Store) } | '(' a=target_with_star_atom ')' { _PyPegen_set_expr_context(p, a, Store) } | '(' a=[star_targets_tuple_seq] ')' { _PyAST_Tuple(a, Store, EXTRA) } | '[' a=[star_targets_list_seq] ']' { _PyAST_List(a, Store, EXTRA) } single_target[expr_ty]: | single_subscript_attribute_target | a=NAME { _PyPegen_set_expr_context(p, a, Store) } | '(' a=single_target ')' { a } single_subscript_attribute_target[expr_ty]: | a=t_primary '.' b=NAME !t_lookahead { _PyAST_Attribute(a, b->v.Name.id, Store, EXTRA) } | a=t_primary '[' b=slices ']' !t_lookahead { _PyAST_Subscript(a, b, Store, EXTRA) } t_primary[expr_ty]: | a=t_primary '.' b=NAME &t_lookahead { _PyAST_Attribute(a, b->v.Name.id, Load, EXTRA) } | a=t_primary '[' b=slices ']' &t_lookahead { _PyAST_Subscript(a, b, Load, EXTRA) } | a=t_primary b=genexp &t_lookahead { _PyAST_Call(a, CHECK(asdl_expr_seq*, (asdl_expr_seq*)_PyPegen_singleton_seq(p, b)), NULL, EXTRA) } | a=t_primary '(' b=[arguments] ')' &t_lookahead { _PyAST_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: '(' | '[' | '.' # Targets for del statements # -------------------------- del_targets[asdl_expr_seq*]: a[asdl_expr_seq*]=','.del_target+ [','] { a } del_target[expr_ty] (memo): | a=t_primary '.' b=NAME !t_lookahead { _PyAST_Attribute(a, b->v.Name.id, Del, EXTRA) } | a=t_primary '[' b=slices ']' !t_lookahead { _PyAST_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] ')' { _PyAST_Tuple(a, Del, EXTRA) } | '[' a=[del_targets] ']' { _PyAST_List(a, Del, EXTRA) } # TYPING ELEMENTS # --------------- # type_expressions allow */** but ignore them type_expressions[asdl_expr_seq*]: | a=','.expression+ ',' '*' b=expression ',' '**' c=expression { (asdl_expr_seq*)_PyPegen_seq_append_to_end( p, CHECK(asdl_seq*, _PyPegen_seq_append_to_end(p, a, b)), c) } | a=','.expression+ ',' '*' b=expression { (asdl_expr_seq*)_PyPegen_seq_append_to_end(p, a, b) } | a=','.expression+ ',' '**' b=expression { (asdl_expr_seq*)_PyPegen_seq_append_to_end(p, a, b) } | '*' a=expression ',' '**' b=expression { (asdl_expr_seq*)_PyPegen_seq_append_to_end( p, CHECK(asdl_seq*, _PyPegen_singleton_seq(p, a)), b) } | '*' a=expression { (asdl_expr_seq*)_PyPegen_singleton_seq(p, a) } | '**' a=expression { (asdl_expr_seq*)_PyPegen_singleton_seq(p, a) } | a[asdl_expr_seq*]=','.expression+ {a} func_type_comment[Token*]: | NEWLINE t=TYPE_COMMENT &(NEWLINE INDENT) { t } # Must be followed by indented block | invalid_double_type_comments | TYPE_COMMENT # ========================= END OF THE GRAMMAR =========================== # ========================= START OF INVALID RULES ======================= # From here on, there are rules for invalid syntax with specialised error messages invalid_arguments: | a=args ',' '*' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "iterable argument unpacking follows keyword argument unpacking") } | a=expression b=for_if_clauses ',' [args | expression for_if_clauses] { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, _PyPegen_get_last_comprehension_item(PyPegen_last_item(b, comprehension_ty)), "Generator expression must be parenthesized") } | a=NAME b='=' expression for_if_clauses { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "invalid syntax. Maybe you meant '==' or ':=' instead of '='?")} | (args ',')? a=NAME b='=' &(',' | ')') { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "expected argument value expression")} | a=args b=for_if_clauses { _PyPegen_nonparen_genexp_in_call(p, a, b) } | args ',' a=expression b=for_if_clauses { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, _PyPegen_get_last_comprehension_item(PyPegen_last_item(b, comprehension_ty)), "Generator expression must be parenthesized") } | a=args ',' args { _PyPegen_arguments_parsing_error(p, a) } invalid_kwarg: | a[Token*]=('True'|'False'|'None') b='=' { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "cannot assign to %s", PyBytes_AS_STRING(a->bytes)) } | a=NAME b='=' expression for_if_clauses { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "invalid syntax. Maybe you meant '==' or ':=' instead of '='?")} | !(NAME '=') a=expression b='=' { RAISE_SYNTAX_ERROR_KNOWN_RANGE( a, b, "expression cannot contain assignment, perhaps you meant \"==\"?") } | a='**' expression '=' b=expression { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "cannot assign to keyword argument unpacking") } # IMPORTANT: Note that the "_without_invalid" suffix causes the rule to not call invalid rules under it expression_without_invalid[expr_ty]: | a=disjunction 'if' b=disjunction 'else' c=expression { _PyAST_IfExp(b, a, c, EXTRA) } | disjunction | lambdef invalid_legacy_expression: | a=NAME !'(' b=star_expressions { _PyPegen_check_legacy_stmt(p, a) ? RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "Missing parentheses in call to '%U'. Did you mean %U(...)?", a->v.Name.id, a->v.Name.id) : NULL} invalid_expression: # !(NAME STRING) is not matched so we don't show this error with some invalid string prefixes like: kf"dsfsdf" # Soft keywords need to also be ignored because they can be parsed as NAME NAME | !(NAME STRING | SOFT_KEYWORD) a=disjunction b=expression_without_invalid { _PyPegen_check_legacy_stmt(p, a) ? NULL : p->tokens[p->mark-1]->level == 0 ? NULL : RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "invalid syntax. Perhaps you forgot a comma?") } | a=disjunction 'if' b=disjunction !('else'|':') { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "expected 'else' after 'if' expression") } | a='lambda' [lambda_params] b=':' &(FSTRING_MIDDLE | fstring_replacement_field) { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "f-string: lambda expressions are not allowed without parentheses") } invalid_named_expression(memo): | a=expression ':=' expression { RAISE_SYNTAX_ERROR_KNOWN_LOCATION( a, "cannot use assignment expressions with %s", _PyPegen_get_expr_name(a)) } | a=NAME '=' b=bitwise_or !('='|':=') { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "invalid syntax. Maybe you meant '==' or ':=' instead of '='?") } | !(list|tuple|genexp|'True'|'None'|'False') a=bitwise_or b='=' bitwise_or !('='|':=') { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "cannot assign to %s here. Maybe you meant '==' instead of '='?", _PyPegen_get_expr_name(a)) } invalid_assignment: | a=invalid_ann_assign_target ':' expression { RAISE_SYNTAX_ERROR_KNOWN_LOCATION( a, "only single target (not %s) can be annotated", _PyPegen_get_expr_name(a) )} | a=star_named_expression ',' star_named_expressions* ':' expression { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "only single target (not tuple) can be annotated") } | a=expression ':' expression { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "illegal target for annotation") } | (star_targets '=')* a=star_expressions '=' { RAISE_SYNTAX_ERROR_INVALID_TARGET(STAR_TARGETS, a) } | (star_targets '=')* a=yield_expr '=' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "assignment to yield expression not possible") } | a=star_expressions augassign (yield_expr | star_expressions) { RAISE_SYNTAX_ERROR_KNOWN_LOCATION( a, "'%s' is an illegal expression for augmented assignment", _PyPegen_get_expr_name(a) )} invalid_ann_assign_target[expr_ty]: | list | tuple | '(' a=invalid_ann_assign_target ')' { a } invalid_del_stmt: | 'del' a=star_expressions { RAISE_SYNTAX_ERROR_INVALID_TARGET(DEL_TARGETS, a) } invalid_block: | NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block") } invalid_comprehension: | ('[' | '(' | '{') a=starred_expression for_if_clauses { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "iterable unpacking cannot be used in comprehension") } | ('[' | '{') a=star_named_expression ',' b=star_named_expressions for_if_clauses { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, PyPegen_last_item(b, expr_ty), "did you forget parentheses around the comprehension target?") } | ('[' | '{') a=star_named_expression b=',' for_if_clauses { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "did you forget parentheses around the comprehension target?") } invalid_dict_comprehension: | '{' a='**' bitwise_or for_if_clauses '}' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "dict unpacking cannot be used in dict comprehension") } invalid_parameters: | a="/" ',' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "at least one argument must precede /") } | (slash_no_default | slash_with_default) param_maybe_default* a='/' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "/ may appear only once") } | slash_no_default? param_no_default* invalid_parameters_helper a=param_no_default { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "parameter without a default follows parameter with a default") } | param_no_default* a='(' param_no_default+ ','? b=')' { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "Function parameters cannot be parenthesized") } | (slash_no_default | slash_with_default)? param_maybe_default* '*' (',' | param_no_default) param_maybe_default* a='/' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "/ must be ahead of *") } | param_maybe_default+ '/' a='*' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "expected comma between / and *") } invalid_default: | a='=' &(')'|',') { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "expected default value expression") } invalid_star_etc: | a='*' (')' | ',' (')' | '**')) { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "named arguments must follow bare *") } | '*' ',' TYPE_COMMENT { RAISE_SYNTAX_ERROR("bare * has associated type comment") } | '*' param a='=' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "var-positional argument cannot have default value") } | '*' (param_no_default | ',') param_maybe_default* a='*' (param_no_default | ',') { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "* argument may appear only once") } invalid_kwds: | '**' param a='=' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "var-keyword argument cannot have default value") } | '**' param ',' a=param { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "arguments cannot follow var-keyword argument") } | '**' param ',' a[Token*]=('*'|'**'|'/') { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "arguments cannot follow var-keyword argument") } invalid_parameters_helper: # This is only there to avoid type errors | a=slash_with_default { _PyPegen_singleton_seq(p, a) } | param_with_default+ invalid_lambda_parameters: | a="/" ',' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "at least one argument must precede /") } | (lambda_slash_no_default | lambda_slash_with_default) lambda_param_maybe_default* a='/' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "/ may appear only once") } | lambda_slash_no_default? lambda_param_no_default* invalid_lambda_parameters_helper a=lambda_param_no_default { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "parameter without a default follows parameter with a default") } | lambda_param_no_default* a='(' ','.lambda_param+ ','? b=')' { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "Lambda expression parameters cannot be parenthesized") } | (lambda_slash_no_default | lambda_slash_with_default)? lambda_param_maybe_default* '*' (',' | lambda_param_no_default) lambda_param_maybe_default* a='/' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "/ must be ahead of *") } | lambda_param_maybe_default+ '/' a='*' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "expected comma between / and *") } invalid_lambda_parameters_helper: | a=lambda_slash_with_default { _PyPegen_singleton_seq(p, a) } | lambda_param_with_default+ invalid_lambda_star_etc: | '*' (':' | ',' (':' | '**')) { RAISE_SYNTAX_ERROR("named arguments must follow bare *") } | '*' lambda_param a='=' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "var-positional argument cannot have default value") } | '*' (lambda_param_no_default | ',') lambda_param_maybe_default* a='*' (lambda_param_no_default | ',') { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "* argument may appear only once") } invalid_lambda_kwds: | '**' lambda_param a='=' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "var-keyword argument cannot have default value") } | '**' lambda_param ',' a=lambda_param { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "arguments cannot follow var-keyword argument") } | '**' lambda_param ',' a[Token*]=('*'|'**'|'/') { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "arguments cannot follow var-keyword argument") } invalid_double_type_comments: | TYPE_COMMENT NEWLINE TYPE_COMMENT NEWLINE INDENT { RAISE_SYNTAX_ERROR("Cannot have two type comments on def") } invalid_with_item: | expression 'as' a=expression &(',' | ')' | ':') { RAISE_SYNTAX_ERROR_INVALID_TARGET(STAR_TARGETS, a) } invalid_for_target: | ASYNC? 'for' a=star_expressions { RAISE_SYNTAX_ERROR_INVALID_TARGET(FOR_TARGETS, a) } invalid_group: | '(' a=starred_expression ')' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "cannot use starred expression here") } | '(' a='**' expression ')' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "cannot use double starred expression here") } invalid_import: | a='import' dotted_name 'from' dotted_name { RAISE_SYNTAX_ERROR_STARTING_FROM(a, "Did you mean to use 'from ... import ...' instead?") } invalid_import_from_targets: | import_from_as_names ',' NEWLINE { RAISE_SYNTAX_ERROR("trailing comma not allowed without surrounding parentheses") } invalid_with_stmt: | [ASYNC] 'with' ','.(expression ['as' star_target])+ NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") } | [ASYNC] 'with' '(' ','.(expressions ['as' star_target])+ ','? ')' NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") } invalid_with_stmt_indent: | [ASYNC] a='with' ','.(expression ['as' star_target])+ ':' NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block after 'with' statement on line %d", a->lineno) } | [ASYNC] a='with' '(' ','.(expressions ['as' star_target])+ ','? ')' ':' NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block after 'with' statement on line %d", a->lineno) } invalid_try_stmt: | a='try' ':' NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block after 'try' statement on line %d", a->lineno) } | 'try' ':' block !('except' | 'finally') { RAISE_SYNTAX_ERROR("expected 'except' or 'finally' block") } | 'try' ':' block* except_block+ a='except' b='*' expression ['as' NAME] ':' { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "cannot have both 'except' and 'except*' on the same 'try'") } | 'try' ':' block* except_star_block+ a='except' [expression ['as' NAME]] ':' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "cannot have both 'except' and 'except*' on the same 'try'") } invalid_except_stmt: | 'except' '*'? a=expression ',' expressions ['as' NAME ] ':' { RAISE_SYNTAX_ERROR_STARTING_FROM(a, "multiple exception types must be parenthesized") } | a='except' '*'? expression ['as' NAME ] NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") } | a='except' NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") } | a='except' '*' (NEWLINE | ':') { RAISE_SYNTAX_ERROR("expected one or more exception types") } invalid_finally_stmt: | a='finally' ':' NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block after 'finally' statement on line %d", a->lineno) } invalid_except_stmt_indent: | a='except' expression ['as' NAME ] ':' NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block after 'except' statement on line %d", a->lineno) } | a='except' ':' NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block after 'except' statement on line %d", a->lineno) } invalid_except_star_stmt_indent: | a='except' '*' expression ['as' NAME ] ':' NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block after 'except*' statement on line %d", a->lineno) } invalid_match_stmt: | "match" subject_expr NEWLINE { CHECK_VERSION(void*, 10, "Pattern matching is", RAISE_SYNTAX_ERROR("expected ':'") ) } | a="match" subject=subject_expr ':' NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block after 'match' statement on line %d", a->lineno) } invalid_case_block: | "case" patterns guard? NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") } | a="case" patterns guard? ':' NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block after 'case' statement on line %d", a->lineno) } invalid_as_pattern: | or_pattern 'as' a="_" { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "cannot use '_' as a target") } | or_pattern 'as' !NAME a=expression { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "invalid pattern target") } invalid_class_pattern: | name_or_attr '(' a=invalid_class_argument_pattern { RAISE_SYNTAX_ERROR_KNOWN_RANGE( PyPegen_first_item(a, pattern_ty), PyPegen_last_item(a, pattern_ty), "positional patterns follow keyword patterns") } invalid_class_argument_pattern[asdl_pattern_seq*]: | [positional_patterns ','] keyword_patterns ',' a=positional_patterns { a } invalid_if_stmt: | 'if' named_expression NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") } | a='if' a=named_expression ':' NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block after 'if' statement on line %d", a->lineno) } invalid_elif_stmt: | 'elif' named_expression NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") } | a='elif' named_expression ':' NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block after 'elif' statement on line %d", a->lineno) } invalid_else_stmt: | a='else' ':' NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block after 'else' statement on line %d", a->lineno) } invalid_while_stmt: | 'while' named_expression NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") } | a='while' named_expression ':' NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block after 'while' statement on line %d", a->lineno) } invalid_for_stmt: | [ASYNC] 'for' star_targets 'in' star_expressions NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") } | [ASYNC] a='for' star_targets 'in' star_expressions ':' NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block after 'for' statement on line %d", a->lineno) } invalid_def_raw: | [ASYNC] a='def' NAME '(' [params] ')' ['->' expression] ':' NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block after function definition on line %d", a->lineno) } invalid_class_def_raw: | 'class' NAME ['(' [arguments] ')'] NEWLINE { RAISE_SYNTAX_ERROR("expected ':'") } | a='class' NAME ['(' [arguments] ')'] ':' NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block after class definition on line %d", a->lineno) } invalid_double_starred_kvpairs: | ','.double_starred_kvpair+ ',' invalid_kvpair | expression ':' a='*' bitwise_or { RAISE_SYNTAX_ERROR_STARTING_FROM(a, "cannot use a starred expression in a dictionary value") } | expression a=':' &('}'|',') { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "expression expected after dictionary key and ':'") } invalid_kvpair: | a=expression !(':') { RAISE_ERROR_KNOWN_LOCATION(p, PyExc_SyntaxError, a->lineno, a->end_col_offset - 1, a->end_lineno, -1, "':' expected after dictionary key") } | expression ':' a='*' bitwise_or { RAISE_SYNTAX_ERROR_STARTING_FROM(a, "cannot use a starred expression in a dictionary value") } | expression a=':' &('}'|',') {RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "expression expected after dictionary key and ':'") } invalid_starred_expression: | a='*' expression '=' b=expression { RAISE_SYNTAX_ERROR_KNOWN_RANGE(a, b, "cannot assign to iterable argument unpacking") } invalid_replacement_field: | '{' a='=' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "f-string: valid expression required before '='") } | '{' a='!' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "f-string: valid expression required before '!'") } | '{' a=':' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "f-string: valid expression required before ':'") } | '{' a='}' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "f-string: valid expression required before '}'") } | '{' !(yield_expr | star_expressions) { RAISE_SYNTAX_ERROR_ON_NEXT_TOKEN("f-string: expecting a valid expression after '{'")} | '{' (yield_expr | star_expressions) !('=' | '!' | ':' | '}') { PyErr_Occurred() ? NULL : RAISE_SYNTAX_ERROR_ON_NEXT_TOKEN("f-string: expecting '=', or '!', or ':', or '}'") } | '{' (yield_expr | star_expressions) '=' !('!' | ':' | '}') { PyErr_Occurred() ? NULL : RAISE_SYNTAX_ERROR_ON_NEXT_TOKEN("f-string: expecting '!', or ':', or '}'") } | '{' (yield_expr | star_expressions) '='? invalid_conversion_character | '{' (yield_expr | star_expressions) '='? ['!' NAME] !(':' | '}') { PyErr_Occurred() ? NULL : RAISE_SYNTAX_ERROR_ON_NEXT_TOKEN("f-string: expecting ':' or '}'") } | '{' (yield_expr | star_expressions) '='? ['!' NAME] ':' fstring_format_spec* !'}' { PyErr_Occurred() ? NULL : RAISE_SYNTAX_ERROR_ON_NEXT_TOKEN("f-string: expecting '}', or format specs") } | '{' (yield_expr | star_expressions) '='? ['!' NAME] !'}' { PyErr_Occurred() ? NULL : RAISE_SYNTAX_ERROR_ON_NEXT_TOKEN("f-string: expecting '}'") } invalid_conversion_character: | '!' &(':' | '}') { RAISE_SYNTAX_ERROR_ON_NEXT_TOKEN("f-string: missing conversion character") } | '!' !NAME { RAISE_SYNTAX_ERROR_ON_NEXT_TOKEN("f-string: invalid conversion character") }