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1# PEG grammar for Python
2
3@trailer '''
4void *
5_PyPegen_parse(Parser *p)
6{
7    // Initialize keywords
8    p->keywords = reserved_keywords;
9    p->n_keyword_lists = n_keyword_lists;
10
11    // Run parser
12    void *result = NULL;
13    if (p->start_rule == Py_file_input) {
14        result = file_rule(p);
15    } else if (p->start_rule == Py_single_input) {
16        result = interactive_rule(p);
17    } else if (p->start_rule == Py_eval_input) {
18        result = eval_rule(p);
19    } else if (p->start_rule == Py_func_type_input) {
20        result = func_type_rule(p);
21    } else if (p->start_rule == Py_fstring_input) {
22        result = fstring_rule(p);
23    }
24
25    return result;
26}
27
28// The end
29'''
30file[mod_ty]: a=[statements] ENDMARKER { _PyPegen_make_module(p, a) }
31interactive[mod_ty]: a=statement_newline { Interactive(a, p->arena) }
32eval[mod_ty]: a=expressions NEWLINE* ENDMARKER { Expression(a, p->arena) }
33func_type[mod_ty]: '(' a=[type_expressions] ')' '->' b=expression NEWLINE* ENDMARKER { FunctionType(a, b, p->arena) }
34fstring[expr_ty]: star_expressions
35
36# type_expressions allow */** but ignore them
37type_expressions[asdl_seq*]:
38    | a=','.expression+ ',' '*' b=expression ',' '**' c=expression {
39        _PyPegen_seq_append_to_end(p, CHECK(_PyPegen_seq_append_to_end(p, a, b)), c) }
40    | a=','.expression+ ',' '*' b=expression { _PyPegen_seq_append_to_end(p, a, b) }
41    | a=','.expression+ ',' '**' b=expression { _PyPegen_seq_append_to_end(p, a, b) }
42    | '*' a=expression ',' '**' b=expression {
43        _PyPegen_seq_append_to_end(p, CHECK(_PyPegen_singleton_seq(p, a)), b) }
44    | '*' a=expression { _PyPegen_singleton_seq(p, a) }
45    | '**' a=expression { _PyPegen_singleton_seq(p, a) }
46    | ','.expression+
47
48statements[asdl_seq*]: a=statement+ { _PyPegen_seq_flatten(p, a) }
49statement[asdl_seq*]: a=compound_stmt { _PyPegen_singleton_seq(p, a) } | simple_stmt
50statement_newline[asdl_seq*]:
51    | a=compound_stmt NEWLINE { _PyPegen_singleton_seq(p, a) }
52    | simple_stmt
53    | NEWLINE { _PyPegen_singleton_seq(p, CHECK(_Py_Pass(EXTRA))) }
54    | ENDMARKER { _PyPegen_interactive_exit(p) }
55simple_stmt[asdl_seq*]:
56    | a=small_stmt !';' NEWLINE { _PyPegen_singleton_seq(p, a) } # Not needed, there for speedup
57    | a=';'.small_stmt+ [';'] NEWLINE { a }
58# NOTE: assignment MUST precede expression, else parsing a simple assignment
59# will throw a SyntaxError.
60small_stmt[stmt_ty] (memo):
61    | assignment
62    | e=star_expressions { _Py_Expr(e, EXTRA) }
63    | &'return' return_stmt
64    | &('import' | 'from') import_stmt
65    | &'raise' raise_stmt
66    | 'pass' { _Py_Pass(EXTRA) }
67    | &'del' del_stmt
68    | &'yield' yield_stmt
69    | &'assert' assert_stmt
70    | 'break' { _Py_Break(EXTRA) }
71    | 'continue' { _Py_Continue(EXTRA) }
72    | &'global' global_stmt
73    | &'nonlocal' nonlocal_stmt
74compound_stmt[stmt_ty]:
75    | &('def' | '@' | ASYNC) function_def
76    | &'if' if_stmt
77    | &('class' | '@') class_def
78    | &('with' | ASYNC) with_stmt
79    | &('for' | ASYNC) for_stmt
80    | &'try' try_stmt
81    | &'while' while_stmt
82
83# NOTE: annotated_rhs may start with 'yield'; yield_expr must start with 'yield'
84assignment[stmt_ty]:
85    | a=NAME ':' b=expression c=['=' d=annotated_rhs { d }] {
86        CHECK_VERSION(
87            6,
88            "Variable annotation syntax is",
89            _Py_AnnAssign(CHECK(_PyPegen_set_expr_context(p, a, Store)), b, c, 1, EXTRA)
90        ) }
91    | a=('(' b=single_target ')' { b }
92         | single_subscript_attribute_target) ':' b=expression c=['=' d=annotated_rhs { d }] {
93        CHECK_VERSION(6, "Variable annotations syntax is", _Py_AnnAssign(a, b, c, 0, EXTRA)) }
94    | a=(z=star_targets '=' { z })+ b=(yield_expr | star_expressions) !'=' tc=[TYPE_COMMENT] {
95         _Py_Assign(a, b, NEW_TYPE_COMMENT(p, tc), EXTRA) }
96    | a=single_target b=augassign ~ c=(yield_expr | star_expressions) {
97         _Py_AugAssign(a, b->kind, c, EXTRA) }
98    | invalid_assignment
99
100augassign[AugOperator*]:
101    | '+=' { _PyPegen_augoperator(p, Add) }
102    | '-=' { _PyPegen_augoperator(p, Sub) }
103    | '*=' { _PyPegen_augoperator(p, Mult) }
104    | '@=' { CHECK_VERSION(5, "The '@' operator is", _PyPegen_augoperator(p, MatMult)) }
105    | '/=' { _PyPegen_augoperator(p, Div) }
106    | '%=' { _PyPegen_augoperator(p, Mod) }
107    | '&=' { _PyPegen_augoperator(p, BitAnd) }
108    | '|=' { _PyPegen_augoperator(p, BitOr) }
109    | '^=' { _PyPegen_augoperator(p, BitXor) }
110    | '<<=' { _PyPegen_augoperator(p, LShift) }
111    | '>>=' { _PyPegen_augoperator(p, RShift) }
112    | '**=' { _PyPegen_augoperator(p, Pow) }
113    | '//=' { _PyPegen_augoperator(p, FloorDiv) }
114
115global_stmt[stmt_ty]: 'global' a=','.NAME+ {
116    _Py_Global(CHECK(_PyPegen_map_names_to_ids(p, a)), EXTRA) }
117nonlocal_stmt[stmt_ty]: 'nonlocal' a=','.NAME+ {
118    _Py_Nonlocal(CHECK(_PyPegen_map_names_to_ids(p, a)), EXTRA) }
119
120yield_stmt[stmt_ty]: y=yield_expr { _Py_Expr(y, EXTRA) }
121
122assert_stmt[stmt_ty]: 'assert' a=expression b=[',' z=expression { z }] { _Py_Assert(a, b, EXTRA) }
123
124del_stmt[stmt_ty]:
125    | 'del' a=del_targets &(';' | NEWLINE) { _Py_Delete(a, EXTRA) }
126    | invalid_del_stmt
127
128import_stmt[stmt_ty]: import_name | import_from
129import_name[stmt_ty]: 'import' a=dotted_as_names { _Py_Import(a, EXTRA) }
130# note below: the ('.' | '...') is necessary because '...' is tokenized as ELLIPSIS
131import_from[stmt_ty]:
132    | 'from' a=('.' | '...')* b=dotted_name 'import' c=import_from_targets {
133        _Py_ImportFrom(b->v.Name.id, c, _PyPegen_seq_count_dots(a), EXTRA) }
134    | 'from' a=('.' | '...')+ 'import' b=import_from_targets {
135        _Py_ImportFrom(NULL, b, _PyPegen_seq_count_dots(a), EXTRA) }
136import_from_targets[asdl_seq*]:
137    | '(' a=import_from_as_names [','] ')' { a }
138    | import_from_as_names !','
139    | '*' { _PyPegen_singleton_seq(p, CHECK(_PyPegen_alias_for_star(p))) }
140    | invalid_import_from_targets
141import_from_as_names[asdl_seq*]:
142    | a=','.import_from_as_name+ { a }
143import_from_as_name[alias_ty]:
144    | a=NAME b=['as' z=NAME { z }] { _Py_alias(a->v.Name.id,
145                                               (b) ? ((expr_ty) b)->v.Name.id : NULL,
146                                               p->arena) }
147dotted_as_names[asdl_seq*]:
148    | a=','.dotted_as_name+ { a }
149dotted_as_name[alias_ty]:
150    | a=dotted_name b=['as' z=NAME { z }] { _Py_alias(a->v.Name.id,
151                                                      (b) ? ((expr_ty) b)->v.Name.id : NULL,
152                                                      p->arena) }
153dotted_name[expr_ty]:
154    | a=dotted_name '.' b=NAME { _PyPegen_join_names_with_dot(p, a, b) }
155    | NAME
156
157if_stmt[stmt_ty]:
158    | 'if' a=named_expression ':' b=block c=elif_stmt { _Py_If(a, b, CHECK(_PyPegen_singleton_seq(p, c)), EXTRA) }
159    | 'if' a=named_expression ':' b=block c=[else_block] { _Py_If(a, b, c, EXTRA) }
160elif_stmt[stmt_ty]:
161    | 'elif' a=named_expression ':' b=block c=elif_stmt { _Py_If(a, b, CHECK(_PyPegen_singleton_seq(p, c)), EXTRA) }
162    | 'elif' a=named_expression ':' b=block c=[else_block] { _Py_If(a, b, c, EXTRA) }
163else_block[asdl_seq*]: 'else' ':' b=block { b }
164
165while_stmt[stmt_ty]:
166    | 'while' a=named_expression ':' b=block c=[else_block] { _Py_While(a, b, c, EXTRA) }
167
168for_stmt[stmt_ty]:
169    | 'for' t=star_targets 'in' ~ ex=star_expressions ':' tc=[TYPE_COMMENT] b=block el=[else_block] {
170        _Py_For(t, ex, b, el, NEW_TYPE_COMMENT(p, tc), EXTRA) }
171    | ASYNC 'for' t=star_targets 'in' ~ ex=star_expressions ':' tc=[TYPE_COMMENT] b=block el=[else_block] {
172        CHECK_VERSION(5, "Async for loops are", _Py_AsyncFor(t, ex, b, el, NEW_TYPE_COMMENT(p, tc), EXTRA)) }
173    | invalid_for_target
174
175with_stmt[stmt_ty]:
176    | 'with' '(' a=','.with_item+ ','? ')' ':' b=block {
177        _Py_With(a, b, NULL, EXTRA) }
178    | 'with' a=','.with_item+ ':' tc=[TYPE_COMMENT] b=block {
179        _Py_With(a, b, NEW_TYPE_COMMENT(p, tc), EXTRA) }
180    | ASYNC 'with' '(' a=','.with_item+ ','? ')' ':' b=block {
181       CHECK_VERSION(5, "Async with statements are", _Py_AsyncWith(a, b, NULL, EXTRA)) }
182    | ASYNC 'with' a=','.with_item+ ':' tc=[TYPE_COMMENT] b=block {
183       CHECK_VERSION(5, "Async with statements are", _Py_AsyncWith(a, b, NEW_TYPE_COMMENT(p, tc), EXTRA)) }
184with_item[withitem_ty]:
185    | e=expression 'as' t=star_target &(',' | ')' | ':') { _Py_withitem(e, t, p->arena) }
186    | invalid_with_item
187    | e=expression { _Py_withitem(e, NULL, p->arena) }
188
189try_stmt[stmt_ty]:
190    | 'try' ':' b=block f=finally_block { _Py_Try(b, NULL, NULL, f, EXTRA) }
191    | 'try' ':' b=block ex=except_block+ el=[else_block] f=[finally_block] { _Py_Try(b, ex, el, f, EXTRA) }
192except_block[excepthandler_ty]:
193    | 'except' e=expression t=['as' z=NAME { z }] ':' b=block {
194        _Py_ExceptHandler(e, (t) ? ((expr_ty) t)->v.Name.id : NULL, b, EXTRA) }
195    | 'except' ':' b=block { _Py_ExceptHandler(NULL, NULL, b, EXTRA) }
196finally_block[asdl_seq*]: 'finally' ':' a=block { a }
197
198return_stmt[stmt_ty]:
199    | 'return' a=[star_expressions] { _Py_Return(a, EXTRA) }
200
201raise_stmt[stmt_ty]:
202    | 'raise' a=expression b=['from' z=expression { z }] { _Py_Raise(a, b, EXTRA) }
203    | 'raise' { _Py_Raise(NULL, NULL, EXTRA) }
204
205function_def[stmt_ty]:
206    | d=decorators f=function_def_raw { _PyPegen_function_def_decorators(p, d, f) }
207    | function_def_raw
208
209function_def_raw[stmt_ty]:
210    | 'def' n=NAME '(' params=[params] ')' a=['->' z=expression { z }] ':' tc=[func_type_comment] b=block {
211        _Py_FunctionDef(n->v.Name.id,
212                        (params) ? params : CHECK(_PyPegen_empty_arguments(p)),
213                        b, NULL, a, NEW_TYPE_COMMENT(p, tc), EXTRA) }
214    | ASYNC 'def' n=NAME '(' params=[params] ')' a=['->' z=expression { z }] ':' tc=[func_type_comment] b=block {
215        CHECK_VERSION(
216            5,
217            "Async functions are",
218            _Py_AsyncFunctionDef(n->v.Name.id,
219                            (params) ? params : CHECK(_PyPegen_empty_arguments(p)),
220                            b, NULL, a, NEW_TYPE_COMMENT(p, tc), EXTRA)
221        ) }
222func_type_comment[Token*]:
223    | NEWLINE t=TYPE_COMMENT &(NEWLINE INDENT) { t }  # Must be followed by indented block
224    | invalid_double_type_comments
225    | TYPE_COMMENT
226
227params[arguments_ty]:
228    | invalid_parameters
229    | parameters
230
231parameters[arguments_ty]:
232    | a=slash_no_default b=param_no_default* c=param_with_default* d=[star_etc] {
233        _PyPegen_make_arguments(p, a, NULL, b, c, d) }
234    | a=slash_with_default b=param_with_default* c=[star_etc] {
235        _PyPegen_make_arguments(p, NULL, a, NULL, b, c) }
236    | a=param_no_default+ b=param_with_default* c=[star_etc] {
237        _PyPegen_make_arguments(p, NULL, NULL, a, b, c) }
238    | a=param_with_default+ b=[star_etc] { _PyPegen_make_arguments(p, NULL, NULL, NULL, a, b)}
239    | a=star_etc { _PyPegen_make_arguments(p, NULL, NULL, NULL, NULL, a) }
240
241# Some duplication here because we can't write (',' | &')'),
242# which is because we don't support empty alternatives (yet).
243#
244slash_no_default[asdl_seq*]:
245    | a=param_no_default+ '/' ',' { a }
246    | a=param_no_default+ '/' &')' { a }
247slash_with_default[SlashWithDefault*]:
248    | a=param_no_default* b=param_with_default+ '/' ',' { _PyPegen_slash_with_default(p, a, b) }
249    | a=param_no_default* b=param_with_default+ '/' &')' { _PyPegen_slash_with_default(p, a, b) }
250
251star_etc[StarEtc*]:
252    | '*' a=param_no_default b=param_maybe_default* c=[kwds] {
253        _PyPegen_star_etc(p, a, b, c) }
254    | '*' ',' b=param_maybe_default+ c=[kwds] {
255        _PyPegen_star_etc(p, NULL, b, c) }
256    | a=kwds { _PyPegen_star_etc(p, NULL, NULL, a) }
257    | invalid_star_etc
258
259kwds[arg_ty]: '**' a=param_no_default { a }
260
261# One parameter.  This *includes* a following comma and type comment.
262#
263# There are three styles:
264# - No default
265# - With default
266# - Maybe with default
267#
268# There are two alternative forms of each, to deal with type comments:
269# - Ends in a comma followed by an optional type comment
270# - No comma, optional type comment, must be followed by close paren
271# The latter form is for a final parameter without trailing comma.
272#
273param_no_default[arg_ty]:
274    | a=param ',' tc=TYPE_COMMENT? { _PyPegen_add_type_comment_to_arg(p, a, tc) }
275    | a=param tc=TYPE_COMMENT? &')' { _PyPegen_add_type_comment_to_arg(p, a, tc) }
276param_with_default[NameDefaultPair*]:
277    | a=param c=default ',' tc=TYPE_COMMENT? { _PyPegen_name_default_pair(p, a, c, tc) }
278    | a=param c=default tc=TYPE_COMMENT? &')' { _PyPegen_name_default_pair(p, a, c, tc) }
279param_maybe_default[NameDefaultPair*]:
280    | a=param c=default? ',' tc=TYPE_COMMENT? { _PyPegen_name_default_pair(p, a, c, tc) }
281    | a=param c=default? tc=TYPE_COMMENT? &')' { _PyPegen_name_default_pair(p, a, c, tc) }
282param[arg_ty]: a=NAME b=annotation? { _Py_arg(a->v.Name.id, b, NULL, EXTRA) }
283
284annotation[expr_ty]: ':' a=expression { a }
285default[expr_ty]: '=' a=expression { a }
286
287decorators[asdl_seq*]: a=('@' f=named_expression NEWLINE { f })+ { a }
288
289class_def[stmt_ty]:
290    | a=decorators b=class_def_raw { _PyPegen_class_def_decorators(p, a, b) }
291    | class_def_raw
292class_def_raw[stmt_ty]:
293    | 'class' a=NAME b=['(' z=[arguments] ')' { z }] ':' c=block {
294        _Py_ClassDef(a->v.Name.id,
295                     (b) ? ((expr_ty) b)->v.Call.args : NULL,
296                     (b) ? ((expr_ty) b)->v.Call.keywords : NULL,
297                     c, NULL, EXTRA) }
298
299block[asdl_seq*] (memo):
300    | NEWLINE INDENT a=statements DEDENT { a }
301    | simple_stmt
302    | invalid_block
303
304star_expressions[expr_ty]:
305    | a=star_expression b=(',' c=star_expression { c })+ [','] {
306        _Py_Tuple(CHECK(_PyPegen_seq_insert_in_front(p, a, b)), Load, EXTRA) }
307    | a=star_expression ',' { _Py_Tuple(CHECK(_PyPegen_singleton_seq(p, a)), Load, EXTRA) }
308    | star_expression
309star_expression[expr_ty] (memo):
310    | '*' a=bitwise_or { _Py_Starred(a, Load, EXTRA) }
311    | expression
312
313star_named_expressions[asdl_seq*]: a=','.star_named_expression+ [','] { a }
314star_named_expression[expr_ty]:
315    | '*' a=bitwise_or { _Py_Starred(a, Load, EXTRA) }
316    | named_expression
317named_expression[expr_ty]:
318    | a=NAME ':=' ~ b=expression { _Py_NamedExpr(CHECK(_PyPegen_set_expr_context(p, a, Store)), b, EXTRA) }
319    | expression !':='
320    | invalid_named_expression
321
322annotated_rhs[expr_ty]: yield_expr | star_expressions
323
324expressions[expr_ty]:
325    | a=expression b=(',' c=expression { c })+ [','] {
326        _Py_Tuple(CHECK(_PyPegen_seq_insert_in_front(p, a, b)), Load, EXTRA) }
327    | a=expression ',' { _Py_Tuple(CHECK(_PyPegen_singleton_seq(p, a)), Load, EXTRA) }
328    | expression
329expression[expr_ty] (memo):
330    | a=disjunction 'if' b=disjunction 'else' c=expression { _Py_IfExp(b, a, c, EXTRA) }
331    | disjunction
332    | lambdef
333
334lambdef[expr_ty]:
335    | 'lambda' a=[lambda_params] ':' b=expression { _Py_Lambda((a) ? a : CHECK(_PyPegen_empty_arguments(p)), b, EXTRA) }
336
337lambda_params[arguments_ty]:
338    | invalid_lambda_parameters
339    | lambda_parameters
340
341# lambda_parameters etc. duplicates parameters but without annotations
342# or type comments, and if there's no comma after a parameter, we expect
343# a colon, not a close parenthesis.  (For more, see parameters above.)
344#
345lambda_parameters[arguments_ty]:
346    | a=lambda_slash_no_default b=lambda_param_no_default* c=lambda_param_with_default* d=[lambda_star_etc] {
347        _PyPegen_make_arguments(p, a, NULL, b, c, d) }
348    | a=lambda_slash_with_default b=lambda_param_with_default* c=[lambda_star_etc] {
349        _PyPegen_make_arguments(p, NULL, a, NULL, b, c) }
350    | a=lambda_param_no_default+ b=lambda_param_with_default* c=[lambda_star_etc] {
351        _PyPegen_make_arguments(p, NULL, NULL, a, b, c) }
352    | a=lambda_param_with_default+ b=[lambda_star_etc] { _PyPegen_make_arguments(p, NULL, NULL, NULL, a, b)}
353    | a=lambda_star_etc { _PyPegen_make_arguments(p, NULL, NULL, NULL, NULL, a) }
354
355lambda_slash_no_default[asdl_seq*]:
356    | a=lambda_param_no_default+ '/' ',' { a }
357    | a=lambda_param_no_default+ '/' &':' { a }
358lambda_slash_with_default[SlashWithDefault*]:
359    | a=lambda_param_no_default* b=lambda_param_with_default+ '/' ',' { _PyPegen_slash_with_default(p, a, b) }
360    | a=lambda_param_no_default* b=lambda_param_with_default+ '/' &':' { _PyPegen_slash_with_default(p, a, b) }
361
362lambda_star_etc[StarEtc*]:
363    | '*' a=lambda_param_no_default b=lambda_param_maybe_default* c=[lambda_kwds] {
364        _PyPegen_star_etc(p, a, b, c) }
365    | '*' ',' b=lambda_param_maybe_default+ c=[lambda_kwds] {
366        _PyPegen_star_etc(p, NULL, b, c) }
367    | a=lambda_kwds { _PyPegen_star_etc(p, NULL, NULL, a) }
368    | invalid_lambda_star_etc
369
370lambda_kwds[arg_ty]: '**' a=lambda_param_no_default { a }
371
372lambda_param_no_default[arg_ty]:
373    | a=lambda_param ',' { a }
374    | a=lambda_param &':' { a }
375lambda_param_with_default[NameDefaultPair*]:
376    | a=lambda_param c=default ',' { _PyPegen_name_default_pair(p, a, c, NULL) }
377    | a=lambda_param c=default &':' { _PyPegen_name_default_pair(p, a, c, NULL) }
378lambda_param_maybe_default[NameDefaultPair*]:
379    | a=lambda_param c=default? ',' { _PyPegen_name_default_pair(p, a, c, NULL) }
380    | a=lambda_param c=default? &':' { _PyPegen_name_default_pair(p, a, c, NULL) }
381lambda_param[arg_ty]: a=NAME { _Py_arg(a->v.Name.id, NULL, NULL, EXTRA) }
382
383disjunction[expr_ty] (memo):
384    | a=conjunction b=('or' c=conjunction { c })+ { _Py_BoolOp(
385        Or,
386        CHECK(_PyPegen_seq_insert_in_front(p, a, b)),
387        EXTRA) }
388    | conjunction
389conjunction[expr_ty] (memo):
390    | a=inversion b=('and' c=inversion { c })+ { _Py_BoolOp(
391        And,
392        CHECK(_PyPegen_seq_insert_in_front(p, a, b)),
393        EXTRA) }
394    | inversion
395inversion[expr_ty] (memo):
396    | 'not' a=inversion { _Py_UnaryOp(Not, a, EXTRA) }
397    | comparison
398comparison[expr_ty]:
399    | a=bitwise_or b=compare_op_bitwise_or_pair+ {
400        _Py_Compare(a, CHECK(_PyPegen_get_cmpops(p, b)), CHECK(_PyPegen_get_exprs(p, b)), EXTRA) }
401    | bitwise_or
402compare_op_bitwise_or_pair[CmpopExprPair*]:
403    | eq_bitwise_or
404    | noteq_bitwise_or
405    | lte_bitwise_or
406    | lt_bitwise_or
407    | gte_bitwise_or
408    | gt_bitwise_or
409    | notin_bitwise_or
410    | in_bitwise_or
411    | isnot_bitwise_or
412    | is_bitwise_or
413eq_bitwise_or[CmpopExprPair*]: '==' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, Eq, a) }
414noteq_bitwise_or[CmpopExprPair*]:
415    | (tok='!=' { _PyPegen_check_barry_as_flufl(p, tok) ? NULL : tok}) a=bitwise_or {_PyPegen_cmpop_expr_pair(p, NotEq, a) }
416lte_bitwise_or[CmpopExprPair*]: '<=' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, LtE, a) }
417lt_bitwise_or[CmpopExprPair*]: '<' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, Lt, a) }
418gte_bitwise_or[CmpopExprPair*]: '>=' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, GtE, a) }
419gt_bitwise_or[CmpopExprPair*]: '>' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, Gt, a) }
420notin_bitwise_or[CmpopExprPair*]: 'not' 'in' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, NotIn, a) }
421in_bitwise_or[CmpopExprPair*]: 'in' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, In, a) }
422isnot_bitwise_or[CmpopExprPair*]: 'is' 'not' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, IsNot, a) }
423is_bitwise_or[CmpopExprPair*]: 'is' a=bitwise_or { _PyPegen_cmpop_expr_pair(p, Is, a) }
424
425bitwise_or[expr_ty]:
426    | a=bitwise_or '|' b=bitwise_xor { _Py_BinOp(a, BitOr, b, EXTRA) }
427    | bitwise_xor
428bitwise_xor[expr_ty]:
429    | a=bitwise_xor '^' b=bitwise_and { _Py_BinOp(a, BitXor, b, EXTRA) }
430    | bitwise_and
431bitwise_and[expr_ty]:
432    | a=bitwise_and '&' b=shift_expr { _Py_BinOp(a, BitAnd, b, EXTRA) }
433    | shift_expr
434shift_expr[expr_ty]:
435    | a=shift_expr '<<' b=sum { _Py_BinOp(a, LShift, b, EXTRA) }
436    | a=shift_expr '>>' b=sum { _Py_BinOp(a, RShift, b, EXTRA) }
437    | sum
438
439sum[expr_ty]:
440    | a=sum '+' b=term { _Py_BinOp(a, Add, b, EXTRA) }
441    | a=sum '-' b=term { _Py_BinOp(a, Sub, b, EXTRA) }
442    | term
443term[expr_ty]:
444    | a=term '*' b=factor { _Py_BinOp(a, Mult, b, EXTRA) }
445    | a=term '/' b=factor { _Py_BinOp(a, Div, b, EXTRA) }
446    | a=term '//' b=factor { _Py_BinOp(a, FloorDiv, b, EXTRA) }
447    | a=term '%' b=factor { _Py_BinOp(a, Mod, b, EXTRA) }
448    | a=term '@' b=factor { CHECK_VERSION(5, "The '@' operator is", _Py_BinOp(a, MatMult, b, EXTRA)) }
449    | factor
450factor[expr_ty] (memo):
451    | '+' a=factor { _Py_UnaryOp(UAdd, a, EXTRA) }
452    | '-' a=factor { _Py_UnaryOp(USub, a, EXTRA) }
453    | '~' a=factor { _Py_UnaryOp(Invert, a, EXTRA) }
454    | power
455power[expr_ty]:
456    | a=await_primary '**' b=factor { _Py_BinOp(a, Pow, b, EXTRA) }
457    | await_primary
458await_primary[expr_ty] (memo):
459    | AWAIT a=primary { CHECK_VERSION(5, "Await expressions are", _Py_Await(a, EXTRA)) }
460    | primary
461primary[expr_ty]:
462    | invalid_primary  # must be before 'primay genexp' because of invalid_genexp
463    | a=primary '.' b=NAME { _Py_Attribute(a, b->v.Name.id, Load, EXTRA) }
464    | a=primary b=genexp { _Py_Call(a, CHECK(_PyPegen_singleton_seq(p, b)), NULL, EXTRA) }
465    | a=primary '(' b=[arguments] ')' {
466        _Py_Call(a,
467                 (b) ? ((expr_ty) b)->v.Call.args : NULL,
468                 (b) ? ((expr_ty) b)->v.Call.keywords : NULL,
469                 EXTRA) }
470    | a=primary '[' b=slices ']' { _Py_Subscript(a, b, Load, EXTRA) }
471    | atom
472
473slices[expr_ty]:
474    | a=slice !',' { a }
475    | a=','.slice+ [','] { _Py_Tuple(a, Load, EXTRA) }
476slice[expr_ty]:
477    | a=[expression] ':' b=[expression] c=[':' d=[expression] { d }] { _Py_Slice(a, b, c, EXTRA) }
478    | a=expression { a }
479atom[expr_ty]:
480    | NAME
481    | 'True' { _Py_Constant(Py_True, NULL, EXTRA) }
482    | 'False' { _Py_Constant(Py_False, NULL, EXTRA) }
483    | 'None' { _Py_Constant(Py_None, NULL, EXTRA) }
484    | '__peg_parser__' { RAISE_SYNTAX_ERROR("You found it!") }
485    | &STRING strings
486    | NUMBER
487    | &'(' (tuple | group | genexp)
488    | &'[' (list | listcomp)
489    | &'{' (dict | set | dictcomp | setcomp)
490    | '...' { _Py_Constant(Py_Ellipsis, NULL, EXTRA) }
491
492strings[expr_ty] (memo): a=STRING+ { _PyPegen_concatenate_strings(p, a) }
493list[expr_ty]:
494    | '[' a=[star_named_expressions] ']' { _Py_List(a, Load, EXTRA) }
495listcomp[expr_ty]:
496    | '[' a=named_expression ~ b=for_if_clauses ']' { _Py_ListComp(a, b, EXTRA) }
497    | invalid_comprehension
498tuple[expr_ty]:
499    | '(' a=[y=star_named_expression ',' z=[star_named_expressions] { _PyPegen_seq_insert_in_front(p, y, z) } ] ')' {
500        _Py_Tuple(a, Load, EXTRA) }
501group[expr_ty]:
502    | '(' a=(yield_expr | named_expression) ')' { a }
503    | invalid_group
504genexp[expr_ty]:
505    | '(' a=named_expression ~ b=for_if_clauses ')' { _Py_GeneratorExp(a, b, EXTRA) }
506    | invalid_comprehension
507set[expr_ty]: '{' a=star_named_expressions '}' { _Py_Set(a, EXTRA) }
508setcomp[expr_ty]:
509    | '{' a=named_expression ~ b=for_if_clauses '}' { _Py_SetComp(a, b, EXTRA) }
510    | invalid_comprehension
511dict[expr_ty]:
512    | '{' a=[double_starred_kvpairs] '}' {
513        _Py_Dict(CHECK(_PyPegen_get_keys(p, a)), CHECK(_PyPegen_get_values(p, a)), EXTRA) }
514dictcomp[expr_ty]:
515    | '{' a=kvpair b=for_if_clauses '}' { _Py_DictComp(a->key, a->value, b, EXTRA) }
516    | invalid_dict_comprehension
517double_starred_kvpairs[asdl_seq*]: a=','.double_starred_kvpair+ [','] { a }
518double_starred_kvpair[KeyValuePair*]:
519    | '**' a=bitwise_or { _PyPegen_key_value_pair(p, NULL, a) }
520    | kvpair
521kvpair[KeyValuePair*]: a=expression ':' b=expression { _PyPegen_key_value_pair(p, a, b) }
522for_if_clauses[asdl_seq*]:
523    | for_if_clause+
524for_if_clause[comprehension_ty]:
525    | ASYNC 'for' a=star_targets 'in' ~ b=disjunction c=('if' z=disjunction { z })* {
526        CHECK_VERSION(6, "Async comprehensions are", _Py_comprehension(a, b, c, 1, p->arena)) }
527    | 'for' a=star_targets 'in' ~ b=disjunction c=('if' z=disjunction { z })* {
528        _Py_comprehension(a, b, c, 0, p->arena) }
529    | invalid_for_target
530
531yield_expr[expr_ty]:
532    | 'yield' 'from' a=expression { _Py_YieldFrom(a, EXTRA) }
533    | 'yield' a=[star_expressions] { _Py_Yield(a, EXTRA) }
534
535arguments[expr_ty] (memo):
536    | a=args [','] &')' { a }
537    | invalid_arguments
538args[expr_ty]:
539    | a=','.(starred_expression | named_expression !'=')+ b=[',' k=kwargs {k}] { _PyPegen_collect_call_seqs(p, a, b, EXTRA) }
540    | a=kwargs { _Py_Call(_PyPegen_dummy_name(p),
541                          CHECK_NULL_ALLOWED(_PyPegen_seq_extract_starred_exprs(p, a)),
542                          CHECK_NULL_ALLOWED(_PyPegen_seq_delete_starred_exprs(p, a)),
543                          EXTRA) }
544kwargs[asdl_seq*]:
545    | a=','.kwarg_or_starred+ ',' b=','.kwarg_or_double_starred+ { _PyPegen_join_sequences(p, a, b) }
546    | ','.kwarg_or_starred+
547    | ','.kwarg_or_double_starred+
548starred_expression[expr_ty]:
549    | '*' a=expression { _Py_Starred(a, Load, EXTRA) }
550kwarg_or_starred[KeywordOrStarred*]:
551    | a=NAME '=' b=expression {
552        _PyPegen_keyword_or_starred(p, CHECK(_Py_keyword(a->v.Name.id, b, EXTRA)), 1) }
553    | a=starred_expression { _PyPegen_keyword_or_starred(p, a, 0) }
554    | invalid_kwarg
555kwarg_or_double_starred[KeywordOrStarred*]:
556    | a=NAME '=' b=expression {
557        _PyPegen_keyword_or_starred(p, CHECK(_Py_keyword(a->v.Name.id, b, EXTRA)), 1) }
558    | '**' a=expression { _PyPegen_keyword_or_starred(p, CHECK(_Py_keyword(NULL, a, EXTRA)), 1) }
559    | invalid_kwarg
560
561# NOTE: star_targets may contain *bitwise_or, targets may not.
562star_targets[expr_ty]:
563    | a=star_target !',' { a }
564    | a=star_target b=(',' c=star_target { c })* [','] {
565        _Py_Tuple(CHECK(_PyPegen_seq_insert_in_front(p, a, b)), Store, EXTRA) }
566star_targets_seq[asdl_seq*]: a=','.star_target+ [','] { a }
567star_target[expr_ty] (memo):
568    | '*' a=(!'*' star_target) {
569        _Py_Starred(CHECK(_PyPegen_set_expr_context(p, a, Store)), Store, EXTRA) }
570    | a=t_primary '.' b=NAME !t_lookahead { _Py_Attribute(a, b->v.Name.id, Store, EXTRA) }
571    | a=t_primary '[' b=slices ']' !t_lookahead { _Py_Subscript(a, b, Store, EXTRA) }
572    | star_atom
573star_atom[expr_ty]:
574    | a=NAME { _PyPegen_set_expr_context(p, a, Store) }
575    | '(' a=star_target ')' { _PyPegen_set_expr_context(p, a, Store) }
576    | '(' a=[star_targets_seq] ')' { _Py_Tuple(a, Store, EXTRA) }
577    | '[' a=[star_targets_seq] ']' { _Py_List(a, Store, EXTRA) }
578
579single_target[expr_ty]:
580    | single_subscript_attribute_target
581    | a=NAME { _PyPegen_set_expr_context(p, a, Store) }
582    | '(' a=single_target ')' { a }
583single_subscript_attribute_target[expr_ty]:
584    | a=t_primary '.' b=NAME !t_lookahead { _Py_Attribute(a, b->v.Name.id, Store, EXTRA) }
585    | a=t_primary '[' b=slices ']' !t_lookahead { _Py_Subscript(a, b, Store, EXTRA) }
586
587del_targets[asdl_seq*]: a=','.del_target+ [','] { a }
588del_target[expr_ty] (memo):
589    | a=t_primary '.' b=NAME !t_lookahead { _Py_Attribute(a, b->v.Name.id, Del, EXTRA) }
590    | a=t_primary '[' b=slices ']' !t_lookahead { _Py_Subscript(a, b, Del, EXTRA) }
591    | del_t_atom
592del_t_atom[expr_ty]:
593    | a=NAME { _PyPegen_set_expr_context(p, a, Del) }
594    | '(' a=del_target ')' { _PyPegen_set_expr_context(p, a, Del) }
595    | '(' a=[del_targets] ')' { _Py_Tuple(a, Del, EXTRA) }
596    | '[' a=[del_targets] ']' { _Py_List(a, Del, EXTRA) }
597
598targets[asdl_seq*]: a=','.target+ [','] { a }
599target[expr_ty] (memo):
600    | a=t_primary '.' b=NAME !t_lookahead { _Py_Attribute(a, b->v.Name.id, Store, EXTRA) }
601    | a=t_primary '[' b=slices ']' !t_lookahead { _Py_Subscript(a, b, Store, EXTRA) }
602    | t_atom
603t_primary[expr_ty]:
604    | a=t_primary '.' b=NAME &t_lookahead { _Py_Attribute(a, b->v.Name.id, Load, EXTRA) }
605    | a=t_primary '[' b=slices ']' &t_lookahead { _Py_Subscript(a, b, Load, EXTRA) }
606    | a=t_primary b=genexp &t_lookahead { _Py_Call(a, CHECK(_PyPegen_singleton_seq(p, b)), NULL, EXTRA) }
607    | a=t_primary '(' b=[arguments] ')' &t_lookahead {
608        _Py_Call(a,
609                 (b) ? ((expr_ty) b)->v.Call.args : NULL,
610                 (b) ? ((expr_ty) b)->v.Call.keywords : NULL,
611                 EXTRA) }
612    | a=atom &t_lookahead { a }
613t_lookahead: '(' | '[' | '.'
614t_atom[expr_ty]:
615    | a=NAME { _PyPegen_set_expr_context(p, a, Store) }
616    | '(' a=target ')' { _PyPegen_set_expr_context(p, a, Store) }
617    | '(' b=[targets] ')' { _Py_Tuple(b, Store, EXTRA) }
618    | '[' b=[targets] ']' { _Py_List(b, Store, EXTRA) }
619
620
621# From here on, there are rules for invalid syntax with specialised error messages
622invalid_arguments:
623    | args ',' '*' { RAISE_SYNTAX_ERROR("iterable argument unpacking follows keyword argument unpacking") }
624    | a=expression for_if_clauses ',' [args | expression for_if_clauses] {
625        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "Generator expression must be parenthesized") }
626    | a=args for_if_clauses { _PyPegen_nonparen_genexp_in_call(p, a) }
627    | args ',' a=expression for_if_clauses {
628        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "Generator expression must be parenthesized") }
629    | a=args ',' args { _PyPegen_arguments_parsing_error(p, a) }
630invalid_kwarg:
631    | a=expression '=' {
632        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
633            a, "expression cannot contain assignment, perhaps you meant \"==\"?") }
634invalid_named_expression:
635    | a=expression ':=' expression {
636        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
637            a, "cannot use assignment expressions with %s", _PyPegen_get_expr_name(a)) }
638invalid_assignment:
639    | a=invalid_ann_assign_target ':' expression {
640        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
641            a,
642            "only single target (not %s) can be annotated",
643            _PyPegen_get_expr_name(a)
644        )}
645    | a=star_named_expression ',' star_named_expressions* ':' expression {
646        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "only single target (not tuple) can be annotated") }
647    | a=expression ':' expression {
648        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "illegal target for annotation") }
649    | (star_targets '=')* a=star_expressions '=' {
650        RAISE_SYNTAX_ERROR_INVALID_TARGET(STAR_TARGETS, a) }
651    | (star_targets '=')* a=yield_expr '=' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "assignment to yield expression not possible") }
652    | a=star_expressions augassign (yield_expr | star_expressions) {
653        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
654            a,
655            "'%s' is an illegal expression for augmented assignment",
656            _PyPegen_get_expr_name(a)
657        )}
658invalid_ann_assign_target[expr_ty]:
659    | list
660    | tuple
661    | '(' a=invalid_ann_assign_target ')' { a }
662invalid_del_stmt:
663    | 'del' a=star_expressions {
664        RAISE_SYNTAX_ERROR_INVALID_TARGET(DEL_TARGETS, a) }
665invalid_block:
666    | NEWLINE !INDENT { RAISE_INDENTATION_ERROR("expected an indented block") }
667invalid_primary:
668    | primary a='{' { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "invalid syntax") }
669invalid_comprehension:
670    | ('[' | '(' | '{') a=starred_expression for_if_clauses {
671        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "iterable unpacking cannot be used in comprehension") }
672invalid_dict_comprehension:
673    | '{' a='**' bitwise_or for_if_clauses '}' {
674        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "dict unpacking cannot be used in dict comprehension") }
675invalid_parameters:
676    | param_no_default* (slash_with_default | param_with_default+) param_no_default {
677        RAISE_SYNTAX_ERROR("non-default argument follows default argument") }
678invalid_lambda_parameters:
679    | lambda_param_no_default* (lambda_slash_with_default | lambda_param_with_default+) lambda_param_no_default {
680        RAISE_SYNTAX_ERROR("non-default argument follows default argument") }
681invalid_star_etc:
682    | '*' (')' | ',' (')' | '**')) { RAISE_SYNTAX_ERROR("named arguments must follow bare *") }
683    | '*' ',' TYPE_COMMENT { RAISE_SYNTAX_ERROR("bare * has associated type comment") }
684invalid_lambda_star_etc:
685    | '*' (':' | ',' (':' | '**')) { RAISE_SYNTAX_ERROR("named arguments must follow bare *") }
686invalid_double_type_comments:
687    | TYPE_COMMENT NEWLINE TYPE_COMMENT NEWLINE INDENT {
688        RAISE_SYNTAX_ERROR("Cannot have two type comments on def") }
689invalid_with_item:
690    | expression 'as' a=expression {
691        RAISE_SYNTAX_ERROR_INVALID_TARGET(STAR_TARGETS, a) }
692
693invalid_for_target:
694    | ASYNC? 'for' a=star_expressions {
695        RAISE_SYNTAX_ERROR_INVALID_TARGET(FOR_TARGETS, a) }
696
697invalid_group:
698    | '(' a=starred_expression ')' {
699        RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "can't use starred expression here") }
700invalid_import_from_targets:
701    | import_from_as_names ',' {
702        RAISE_SYNTAX_ERROR("trailing comma not allowed without surrounding parentheses") }
703