10. 完整的語法規格書
********************

这是完整的 Python 语法规范，直接提取自用于生成 CPython 解析器的语法 (
参见 Grammar/python.gram)。 这里显示的版本省略了有关代码生成和错误恢复
的细节。

The notation is a mixture of EBNF and PEG. In particular, "&" followed
by a symbol, token or parenthesized group indicates a positive
lookahead (i.e., is required to match but not consumed), while "!"
indicates a negative lookahead (i.e., is required *not* to match).  We
use the "|" separator to mean PEG's "ordered choice" (written as "/"
in traditional PEG grammars). See **PEP 617** for more details on the
grammar's syntax.

   # 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;
   }

   // The end
   '''
   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

   # 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}

   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
       | 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

   # 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

   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) }

   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) }

   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) }

   del_stmt[stmt_ty]:
       | 'del' a=del_targets &(';' | NEWLINE) { _PyAST_Delete(a, EXTRA) }
       | invalid_del_stmt

   import_stmt[stmt_ty]: import_name | import_from
   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

   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_stmt[stmt_ty]:
       | invalid_while_stmt
       | 'while' a=named_expression ':' b=block c=[else_block] { _PyAST_While(a, b, c, EXTRA) }

   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_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_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) }
   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
   finally_block[asdl_stmt_seq*]:
       | invalid_finally_stmt
       | 'finally' &&':' a=block { a }

   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) }

   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) }

   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 '(' 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), EXTRA) }
       | ASYNC 'def' n=NAME '(' 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), EXTRA)
           ) }
   func_type_comment[Token*]:
       | NEWLINE t=TYPE_COMMENT &(NEWLINE INDENT) { t }  # Must be followed by indented block
       | invalid_double_type_comments
       | TYPE_COMMENT

   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*]:
       | '*' a=param_no_default 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) }
       | invalid_star_etc

   kwds[arg_ty]: '**' 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_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) }

   annotation[expr_ty]: ':' a=expression { a }
   default[expr_ty]: '=' a=expression { a }

   decorators[asdl_expr_seq*]: a[asdl_expr_seq*]=('@' f=named_expression NEWLINE { f })+ { a }

   class_def[stmt_ty]:
       | a=decorators b=class_def_raw { _PyPegen_class_def_decorators(p, a, b) }
       | class_def_raw
   class_def_raw[stmt_ty]:
       | invalid_class_def_raw
       | 'class' a=NAME 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, EXTRA) }

   block[asdl_stmt_seq*] (memo):
       | NEWLINE INDENT a=statements DEDENT { a }
       | simple_stmts
       | invalid_block

   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 !':='

   annotated_rhs[expr_ty]: yield_expr | star_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

   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*]:
       | '*' 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) }
       | invalid_lambda_star_etc

   lambda_kwds[arg_ty]: '**' 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) }

   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[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_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

   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
   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+ [','] { _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 strings
       | NUMBER
       | &'(' (tuple | group | genexp)
       | &'[' (list | listcomp)
       | &'{' (dict | set | dictcomp | setcomp)
       | '...' { _PyAST_Constant(Py_Ellipsis, NULL, EXTRA) }

   strings[expr_ty] (memo): a=STRING+ { _PyPegen_concatenate_strings(p, a) }
   list[expr_ty]:
       | '[' a=[star_named_expressions] ']' { _PyAST_List(a, Load, EXTRA) }
   listcomp[expr_ty]:
       | '[' a=named_expression b=for_if_clauses ']' { _PyAST_ListComp(a, b, EXTRA) }
       | invalid_comprehension
   tuple[expr_ty]:
       | '(' a=[y=star_named_expression ',' z=[star_named_expressions] { _PyPegen_seq_insert_in_front(p, y, z) } ] ')' {
           _PyAST_Tuple(a, Load, EXTRA) }
   group[expr_ty]:
       | '(' a=(yield_expr | named_expression) ')' { a }
       | invalid_group
   genexp[expr_ty]:
       | '(' a=( assignment_expression | expression !':=') b=for_if_clauses ')' { _PyAST_GeneratorExp(a, b, EXTRA) }
       | invalid_comprehension
   set[expr_ty]: '{' a=star_named_expressions '}' { _PyAST_Set(a, EXTRA) }
   setcomp[expr_ty]:
       | '{' a=named_expression b=for_if_clauses '}' { _PyAST_SetComp(a, b, EXTRA) }
       | invalid_comprehension
   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 '}'

   dictcomp[expr_ty]:
       | '{' a=kvpair b=for_if_clauses '}' { _PyAST_DictComp(a->key, a->value, b, EXTRA) }
       | invalid_dict_comprehension
   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) }
   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

   yield_expr[expr_ty]:
       | 'yield' 'from' a=expression { _PyAST_YieldFrom(a, EXTRA) }
       | 'yield' a=[star_expressions] { _PyAST_Yield(a, EXTRA) }

   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]:
       | '*' 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) }

   # 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) }

   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) }

   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: '(' | '[' | '.'

   # 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 '='?")}
       | 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 \"==\"?") }

   # 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") }

   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:
       | param_no_default* invalid_parameters_helper a=param_no_default {
           RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "non-default argument follows default 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:
       | lambda_param_no_default* invalid_lambda_parameters_helper a=lambda_param_no_default {
           RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "non-default argument follows default argument") }
   invalid_lambda_parameters_helper:
       | a=lambda_slash_with_default { _PyPegen_singleton_seq(p, a) }
       | lambda_param_with_default+
   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") }
   invalid_lambda_star_etc:
       | '*' (':' | ',' (':' | '**')) { RAISE_SYNTAX_ERROR("named arguments must follow bare *") }
   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_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") }
   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 ':'") }
   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_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 ':'") }
