# 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);

}

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.

# &&e

# Eager parse e. The parser will not backtrack and will immediately

# fail with SyntaxError if e cannot be parsed.

#

# 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) }

# GENERAL STATEMENTS

# ==================

statements[asdl_stmt_seq*]: a=statement+ { _PyPegen_register_stmts(p, (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 }

single_compound_stmt[asdl_stmt_seq*]:

| a=compound_stmt {

_PyPegen_register_stmts(p, (asdl_stmt_seq*)_PyPegen_singleton_seq(p, a)) }

statement_newline[asdl_stmt_seq*]:

| a=single_compound_stmt NEWLINE { 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' pass_stmt

| &'del' del_stmt

| &'yield' yield_stmt

| &'assert' assert_stmt

| &'break' break_stmt

| &'continue' continue_stmt

| &'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=annotated_rhs !'=' tc=[TYPE_COMMENT] {

_PyAST_Assign(a, b, NEW_TYPE_COMMENT(p, tc), EXTRA) }

| a=single_target b=augassign ~ c=annotated_rhs {

_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) }

pass_stmt[stmt_ty]:

| 'pass' { _PyAST_Pass(EXTRA) }

break_stmt[stmt_ty]:

| 'break' { _PyAST_Break(EXTRA) }

continue_stmt[stmt_ty]:

| 'continue' { _PyAST_Continue(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 {

_PyPegen_checked_future_import(p, 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]:

| invalid_import_from_as_name

| 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]:

| invalid_dotted_as_name

| 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+ ','? ')' ':' tc=[TYPE_COMMENT] b=block {

_PyAST_With(a, b, NEW_TYPE_COMMENT(p, tc), 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 ':' b=block {

_PyAST_ExceptHandler(e, NULL, b, EXTRA) }

| 'except' e=expression 'as' t=NAME ':' b=block {

_PyAST_ExceptHandler(e, ((expr_ty) t)->v.Name.id, b, EXTRA) }

| 'except' e=expressions ':' b=block {

CHECK_VERSION(

excepthandler_ty,

14,

"except expressions without parentheses are",

_PyAST_ExceptHandler(e, 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 ':' b=block {

_PyAST_ExceptHandler(e, NULL, b, EXTRA) }

| 'except' '*' e=expression 'as' t=NAME ':' b=block {

_PyAST_ExceptHandler(e, ((expr_ty) t)->v.Name.id, b, EXTRA) }

| 'except' '*' e=expressions ':' b=block {

CHECK_VERSION(

excepthandler_ty,

14,

"except expressions without parentheses are",

_PyAST_ExceptHandler(e, NULL, b, EXTRA)) }

| invalid_except_star_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

| &(STRING|FSTRING_START|TSTRING_START) 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*]:

| invalid_type_params

| '[' 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] c=[type_param_default] { _PyAST_TypeVar(a->v.Name.id, b, c, EXTRA) }

| invalid_type_param

| '*' a=NAME b=[type_param_starred_default] { _PyAST_TypeVarTuple(a->v.Name.id, b, EXTRA) }

| '**' a=NAME b=[type_param_default] { _PyAST_ParamSpec(a->v.Name.id, b, EXTRA) }

type_param_bound[expr_ty]: ':' e=expression { e }

type_param_default[expr_ty]: '=' e=expression {

CHECK_VERSION(expr_ty, 13, "Type parameter defaults are", e) }

type_param_starred_default[expr_ty]: '=' e=star_expression {

CHECK_VERSION(expr_ty, 13, "Type parameter defaults are", 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) }

| invalid_arithmetic

| 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)) }

| invalid_factor

| 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|TSTRING_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=annotated_rhs debug_expr='='? conversion=[fstring_conversion] format=[fstring_full_format_spec] rbrace='}' {

_PyPegen_formatted_value(p, a, debug_expr, conversion, format, rbrace, EXTRA) }

| invalid_fstring_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) }

tstring_format_spec_replacement_field[expr_ty]:

| '{' a=annotated_rhs debug_expr='='? conversion=[fstring_conversion] format=[tstring_full_format_spec] rbrace='}' {

_PyPegen_formatted_value(p, a, debug_expr, conversion, format, rbrace, EXTRA) }

| invalid_tstring_replacement_field

tstring_format_spec[expr_ty]:

| t=TSTRING_MIDDLE { _PyPegen_decoded_constant_from_token(p, t) }

| tstring_format_spec_replacement_field

tstring_full_format_spec[ResultTokenWithMetadata*]:

| colon=':' spec=tstring_format_spec* { _PyPegen_setup_full_format_spec(p, colon, (asdl_expr_seq *) spec, EXTRA) }

tstring_replacement_field[expr_ty]:

| '{' a=annotated_rhs debug_expr='='? conversion=[fstring_conversion] format=[tstring_full_format_spec] rbrace='}' {

_PyPegen_interpolation(p, a, debug_expr, conversion, format, rbrace, EXTRA) }

| invalid_tstring_replacement_field

tstring_middle[expr_ty]:

| tstring_replacement_field

| t=TSTRING_MIDDLE { _PyPegen_constant_from_token(p, t) }

tstring[expr_ty] (memo):

| a=TSTRING_START b=tstring_middle* c=TSTRING_END {

CHECK_VERSION(

expr_ty,

14,

"t-strings are",

_PyPegen_template_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|tstring)+ { _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

# -----