| # Grammar for Python | |
| # NOTE WELL: You should also follow all the steps listed at | |
| # https://devguide.python.org/grammar/ | |
| # Start symbols for the grammar: | |
| # single_input is a single interactive statement; | |
| # file_input is a module or sequence of commands read from an input file; | |
| # eval_input is the input for the eval() functions. | |
| # NB: compound_stmt in single_input is followed by extra NEWLINE! | |
| single_input: NEWLINE | simple_stmt | compound_stmt NEWLINE | |
| file_input: stmt* ENDMARKER | |
| eval_input: testlist NEWLINE* ENDMARKER | |
| decorator: '@' namedexpr_test NEWLINE | |
| decorators: decorator+ | |
| decorated: decorators (classdef | funcdef | async_funcdef) | |
| async_funcdef: 'async' funcdef | |
| funcdef: 'def' NAME parameters ['->' test] ':' suite | |
| parameters: '(' [typedargslist] ')' | |
| typedargslist: ( | |
| (tfpdef ['=' test] (',' tfpdef ['=' test])* ',' '/' [',' [ tfpdef ['=' test] ( | |
| ',' tfpdef ['=' test])* ([',' [ | |
| '*' [tfpdef] (',' tfpdef ['=' test])* [',' ['**' tfpdef [',']]] | |
| | '**' tfpdef [',']]]) | |
| | '*' [tfpdef] (',' tfpdef ['=' test])* ([',' ['**' tfpdef [',']]]) | |
| | '**' tfpdef [',']]] ) | |
| | (tfpdef ['=' test] (',' tfpdef ['=' test])* [',' [ | |
| '*' [tfpdef] (',' tfpdef ['=' test])* [',' ['**' tfpdef [',']]] | |
| | '**' tfpdef [',']]] | |
| | '*' [tfpdef] (',' tfpdef ['=' test])* [',' ['**' tfpdef [',']]] | |
| | '**' tfpdef [',']) | |
| ) | |
| tfpdef: NAME [':' test] | |
| varargslist: vfpdef ['=' test ](',' vfpdef ['=' test])* ',' '/' [',' [ (vfpdef ['=' test] (',' vfpdef ['=' test])* [',' [ | |
| '*' [vfpdef] (',' vfpdef ['=' test])* [',' ['**' vfpdef [',']]] | |
| | '**' vfpdef [',']]] | |
| | '*' [vfpdef] (',' vfpdef ['=' test])* [',' ['**' vfpdef [',']]] | |
| | '**' vfpdef [',']) ]] | (vfpdef ['=' test] (',' vfpdef ['=' test])* [',' [ | |
| '*' [vfpdef] (',' vfpdef ['=' test])* [',' ['**' vfpdef [',']]] | |
| | '**' vfpdef [',']]] | |
| | '*' [vfpdef] (',' vfpdef ['=' test])* [',' ['**' vfpdef [',']]] | |
| | '**' vfpdef [','] | |
| ) | |
| vfpdef: NAME | |
| stmt: simple_stmt | compound_stmt | NEWLINE | |
| simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE | |
| small_stmt: (expr_stmt | del_stmt | pass_stmt | flow_stmt | | |
| import_stmt | global_stmt | nonlocal_stmt | assert_stmt) | |
| expr_stmt: testlist_star_expr (annassign | augassign (yield_expr|testlist) | | |
| ('=' (yield_expr|testlist_star_expr))*) | |
| annassign: ':' test ['=' (yield_expr|testlist_star_expr)] | |
| testlist_star_expr: (test|star_expr) (',' (test|star_expr))* [','] | |
| augassign: ('+=' | '-=' | '*=' | '@=' | '/=' | '%=' | '&=' | '|=' | '^=' | | |
| '<<=' | '>>=' | '**=' | '//=') | |
| # For normal and annotated assignments, additional restrictions enforced by the interpreter | |
| del_stmt: 'del' exprlist | |
| pass_stmt: 'pass' | |
| flow_stmt: break_stmt | continue_stmt | return_stmt | raise_stmt | yield_stmt | |
| break_stmt: 'break' | |
| continue_stmt: 'continue' | |
| return_stmt: 'return' [testlist_star_expr] | |
| yield_stmt: yield_expr | |
| raise_stmt: 'raise' [test ['from' test]] | |
| import_stmt: import_name | import_from | |
| import_name: 'import' dotted_as_names | |
| # note below: the ('.' | '...') is necessary because '...' is tokenized as ELLIPSIS | |
| import_from: ('from' (('.' | '...')* dotted_name | ('.' | '...')+) | |
| 'import' ('*' | '(' import_as_names ')' | import_as_names)) | |
| import_as_name: NAME ['as' NAME] | |
| dotted_as_name: dotted_name ['as' NAME] | |
| import_as_names: import_as_name (',' import_as_name)* [','] | |
| dotted_as_names: dotted_as_name (',' dotted_as_name)* | |
| dotted_name: NAME ('.' NAME)* | |
| global_stmt: 'global' NAME (',' NAME)* | |
| nonlocal_stmt: 'nonlocal' NAME (',' NAME)* | |
| assert_stmt: 'assert' test [',' test] | |
| compound_stmt: if_stmt | while_stmt | for_stmt | try_stmt | with_stmt | funcdef | classdef | decorated | async_stmt | |
| async_stmt: 'async' (funcdef | with_stmt | for_stmt) | |
| if_stmt: 'if' namedexpr_test ':' suite ('elif' namedexpr_test ':' suite)* ['else' ':' suite] | |
| while_stmt: 'while' namedexpr_test ':' suite ['else' ':' suite] | |
| for_stmt: 'for' exprlist 'in' testlist ':' suite ['else' ':' suite] | |
| try_stmt: ('try' ':' suite | |
| ((except_clause ':' suite)+ | |
| ['else' ':' suite] | |
| ['finally' ':' suite] | | |
| 'finally' ':' suite)) | |
| with_stmt: 'with' with_item (',' with_item)* ':' suite | |
| with_item: test ['as' expr] | |
| # NB compile.c makes sure that the default except clause is last | |
| except_clause: 'except' [test ['as' NAME]] | |
| suite: simple_stmt | NEWLINE INDENT stmt+ DEDENT | |
| namedexpr_test: test [':=' test] | |
| test: or_test ['if' or_test 'else' test] | lambdef | |
| lambdef: 'lambda' [varargslist] ':' test | |
| or_test: and_test ('or' and_test)* | |
| and_test: not_test ('and' not_test)* | |
| not_test: 'not' not_test | comparison | |
| comparison: expr (comp_op expr)* | |
| # <> isn't actually a valid comparison operator in Python. It's here for the | |
| # sake of a __future__ import described in PEP 401 (which really works :-) | |
| comp_op: '<'|'>'|'=='|'>='|'<='|'<>'|'!='|'in'|'not' 'in'|'is'|'is' 'not' | |
| star_expr: '*' expr | |
| expr: xor_expr ('|' xor_expr)* | |
| xor_expr: and_expr ('^' and_expr)* | |
| and_expr: shift_expr ('&' shift_expr)* | |
| shift_expr: arith_expr (('<<'|'>>') arith_expr)* | |
| arith_expr: term (('+'|'-') term)* | |
| term: factor (('*'|'@'|'/'|'%'|'//') factor)* | |
| factor: ('+'|'-'|'~') factor | power | |
| power: atom_expr ['**' factor] | |
| atom_expr: ['await'] atom trailer* | |
| atom: ('(' [yield_expr|testlist_comp] ')' | | |
| '[' [testlist_comp] ']' | | |
| '{' [dictorsetmaker] '}' | | |
| NAME | NUMBER | strings | '...' | 'None' | 'True' | 'False') | |
| testlist_comp: (namedexpr_test|star_expr) ( comp_for | (',' (namedexpr_test|star_expr))* [','] ) | |
| trailer: '(' [arglist] ')' | '[' subscriptlist ']' | '.' NAME | |
| subscriptlist: subscript (',' subscript)* [','] | |
| subscript: test [':=' test] | [test] ':' [test] [sliceop] | |
| sliceop: ':' [test] | |
| exprlist: (expr|star_expr) (',' (expr|star_expr))* [','] | |
| testlist: test (',' test)* [','] | |
| dictorsetmaker: ( ((test ':' test | '**' expr) | |
| (comp_for | (',' (test ':' test | '**' expr))* [','])) | | |
| ((test [':=' test] | star_expr) | |
| (comp_for | (',' (test [':=' test] | star_expr))* [','])) ) | |
| classdef: 'class' NAME ['(' [arglist] ')'] ':' suite | |
| arglist: argument (',' argument)* [','] | |
| # The reason that keywords are test nodes instead of NAME is that using NAME | |
| # results in an ambiguity. ast.c makes sure it's a NAME. | |
| # "test '=' test" is really "keyword '=' test", but we have no such token. | |
| # These need to be in a single rule to avoid grammar that is ambiguous | |
| # to our LL(1) parser. Even though 'test' includes '*expr' in star_expr, | |
| # we explicitly match '*' here, too, to give it proper precedence. | |
| # Illegal combinations and orderings are blocked in ast.c: | |
| # multiple (test comp_for) arguments are blocked; keyword unpackings | |
| # that precede iterable unpackings are blocked; etc. | |
| argument: ( test [comp_for] | | |
| test ':=' test | | |
| test '=' test | | |
| '**' test | | |
| '*' test ) | |
| comp_iter: comp_for | comp_if | |
| sync_comp_for: 'for' exprlist 'in' or_test [comp_iter] | |
| comp_for: ['async'] sync_comp_for | |
| comp_if: 'if' or_test [comp_iter] | |
| # not used in grammar, but may appear in "node" passed from Parser to Compiler | |
| encoding_decl: NAME | |
| yield_expr: 'yield' [yield_arg] | |
| yield_arg: 'from' test | testlist_star_expr | |
| strings: (STRING | fstring)+ | |
| fstring: FSTRING_START fstring_content* FSTRING_END | |
| fstring_content: FSTRING_STRING | fstring_expr | |
| fstring_conversion: '!' NAME | |
| fstring_expr: '{' (testlist_comp | yield_expr) ['='] [ fstring_conversion ] [ fstring_format_spec ] '}' | |
| fstring_format_spec: ':' fstring_content* | |