1 # Grammar for Python 2 3 # Note: Changing the grammar specified in this file will most likely 4 # require corresponding changes in the parser module 5 # (../Modules/parsermodule.c). If you can't make the changes to 6 # that module yourself, please co-ordinate the required changes 7 # with someone who can; ask around on python-dev for help. Fred 8 # Drake <fdrake@acm.org> will probably be listening there. 9 10 # NOTE WELL: You should also follow all the steps listed in PEP 306, 11 # "How to Change Python's Grammar" 12 13 # Start symbols for the grammar: 14 # single_input is a single interactive statement; 15 # file_input is a module or sequence of commands read from an input file; 16 # eval_input is the input for the eval() and input() functions. 17 # NB: compound_stmt in single_input is followed by extra NEWLINE! 18 single_input: NEWLINE | simple_stmt | compound_stmt NEWLINE 19 file_input: (NEWLINE | stmt)* ENDMARKER 20 eval_input: testlist NEWLINE* ENDMARKER 21 22 decorator: '@' dotted_name [ '(' [arglist] ')' ] NEWLINE 23 decorators: decorator+ 24 decorated: decorators (classdef | funcdef) 25 funcdef: 'def' NAME parameters ':' suite 26 parameters: '(' [varargslist] ')' 27 varargslist: ((fpdef ['=' test] ',')* 28 ('*' NAME [',' '**' NAME] | '**' NAME) | 29 fpdef ['=' test] (',' fpdef ['=' test])* [',']) 30 fpdef: NAME | '(' fplist ')' 31 fplist: fpdef (',' fpdef)* [','] 32 33 stmt: simple_stmt | compound_stmt 34 simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE 35 small_stmt: (expr_stmt | print_stmt | del_stmt | pass_stmt | flow_stmt | 36 import_stmt | global_stmt | exec_stmt | assert_stmt) 37 expr_stmt: testlist (augassign (yield_expr|testlist) | 38 ('=' (yield_expr|testlist))*) 39 augassign: ('+=' | '-=' | '*=' | '/=' | '%=' | '&=' | '|=' | '^=' | 40 '<<=' | '>>=' | '**=' | '//=') 41 # For normal assignments, additional restrictions enforced by the interpreter 42 print_stmt: 'print' ( [ test (',' test)* [','] ] | 43 '>>' test [ (',' test)+ [','] ] ) 44 del_stmt: 'del' exprlist 45 pass_stmt: 'pass' 46 flow_stmt: break_stmt | continue_stmt | return_stmt | raise_stmt | yield_stmt 47 break_stmt: 'break' 48 continue_stmt: 'continue' 49 return_stmt: 'return' [testlist] 50 yield_stmt: yield_expr 51 raise_stmt: 'raise' [test [',' test [',' test]]] 52 import_stmt: import_name | import_from 53 import_name: 'import' dotted_as_names 54 import_from: ('from' ('.'* dotted_name | '.'+) 55 'import' ('*' | '(' import_as_names ')' | import_as_names)) 56 import_as_name: NAME ['as' NAME] 57 dotted_as_name: dotted_name ['as' NAME] 58 import_as_names: import_as_name (',' import_as_name)* [','] 59 dotted_as_names: dotted_as_name (',' dotted_as_name)* 60 dotted_name: NAME ('.' NAME)* 61 global_stmt: 'global' NAME (',' NAME)* 62 exec_stmt: 'exec' expr ['in' test [',' test]] 63 assert_stmt: 'assert' test [',' test] 64 65 compound_stmt: if_stmt | while_stmt | for_stmt | try_stmt | with_stmt | funcdef | classdef | decorated 66 if_stmt: 'if' test ':' suite ('elif' test ':' suite)* ['else' ':' suite] 67 while_stmt: 'while' test ':' suite ['else' ':' suite] 68 for_stmt: 'for' exprlist 'in' testlist ':' suite ['else' ':' suite] 69 try_stmt: ('try' ':' suite 70 ((except_clause ':' suite)+ 71 ['else' ':' suite] 72 ['finally' ':' suite] | 73 'finally' ':' suite)) 74 with_stmt: 'with' with_item (',' with_item)* ':' suite 75 with_item: test ['as' expr] 76 # NB compile.c makes sure that the default except clause is last 77 except_clause: 'except' [test [('as' | ',') test]] 78 suite: simple_stmt | NEWLINE INDENT stmt+ DEDENT 79 80 # Backward compatibility cruft to support: 81 # [ x for x in lambda: True, lambda: False if x() ] 82 # even while also allowing: 83 # lambda x: 5 if x else 2 84 # (But not a mix of the two) 85 testlist_safe: old_test [(',' old_test)+ [',']] 86 old_test: or_test | old_lambdef 87 old_lambdef: 'lambda' [varargslist] ':' old_test 88 89 test: or_test ['if' or_test 'else' test] | lambdef 90 or_test: and_test ('or' and_test)* 91 and_test: not_test ('and' not_test)* 92 not_test: 'not' not_test | comparison 93 comparison: expr (comp_op expr)* 94 comp_op: '<'|'>'|'=='|'>='|'<='|'<>'|'!='|'in'|'not' 'in'|'is'|'is' 'not' 95 expr: xor_expr ('|' xor_expr)* 96 xor_expr: and_expr ('^' and_expr)* 97 and_expr: shift_expr ('&' shift_expr)* 98 shift_expr: arith_expr (('<<'|'>>') arith_expr)* 99 arith_expr: term (('+'|'-') term)* 100 term: factor (('*'|'/'|'%'|'//') factor)* 101 factor: ('+'|'-'|'~') factor | power 102 power: atom trailer* ['**' factor] 103 atom: ('(' [yield_expr|testlist_comp] ')' | 104 '[' [listmaker] ']' | 105 '{' [dictorsetmaker] '}' | 106 '`' testlist1 '`' | 107 NAME | NUMBER | STRING+) 108 listmaker: test ( list_for | (',' test)* [','] ) 109 testlist_comp: test ( comp_for | (',' test)* [','] ) 110 lambdef: 'lambda' [varargslist] ':' test 111 trailer: '(' [arglist] ')' | '[' subscriptlist ']' | '.' NAME 112 subscriptlist: subscript (',' subscript)* [','] 113 subscript: '.' '.' '.' | test | [test] ':' [test] [sliceop] 114 sliceop: ':' [test] 115 exprlist: expr (',' expr)* [','] 116 testlist: test (',' test)* [','] 117 dictmaker: test ':' test (',' test ':' test)* [','] 118 dictorsetmaker: ( (test ':' test (comp_for | (',' test ':' test)* [','])) | 119 (test (comp_for | (',' test)* [','])) ) 120 121 classdef: 'class' NAME ['(' [testlist] ')'] ':' suite 122 123 arglist: (argument ',')* (argument [','] 124 |'*' test (',' argument)* [',' '**' test] 125 |'**' test) 126 # The reason that keywords are test nodes instead of NAME is that using NAME 127 # results in an ambiguity. ast.c makes sure it's a NAME. 128 argument: test [comp_for] | test '=' test 129 130 list_iter: list_for | list_if 131 list_for: 'for' exprlist 'in' testlist_safe [list_iter] 132 list_if: 'if' old_test [list_iter] 133 134 comp_iter: comp_for | comp_if 135 comp_for: 'for' exprlist 'in' or_test [comp_iter] 136 comp_if: 'if' old_test [comp_iter] 137 138 testlist1: test (',' test)* 139 140 # not used in grammar, but may appear in "node" passed from Parser to Compiler 141 encoding_decl: NAME 142 143 yield_expr: 'yield' [testlist]