# 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: (NEWLINE | stmt)* ENDMARKER eval_input: testlist NEWLINE* ENDMARKER
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' test ':' suite ('elif' test ':' suite)* ['else'':' suite] while_stmt: 'while' 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
test: or_test ['if' or_test 'else' test] | lambdef test_nocond: or_test | lambdef_nocond lambdef: 'lambda' [varargslist] ':' test lambdef_nocond: 'lambda' [varargslist] ':' test_nocond 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 | STRING+ | '...' | 'None' | 'True' | 'False') testlist_comp: (test|star_expr) ( comp_for | (',' (test|star_expr))* [','] ) trailer: '(' [arglist] ')' | '[' subscriptlist ']' | '.' NAME subscriptlist: subscript (',' subscript)* [','] subscript: 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 | star_expr) (comp_for | (',' (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 )
