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.
10 # NOTE WELL: You should also follow all the steps listed in PEP 306,
11 # "How to Change Python's Grammar"
13 # Commands for Kees Blom's railroad program
17 #diagram:token NEWLINE
18 #diagram:token ENDMARKER
20 #diagram:output\input python.bla
22 #diagram:output\textwidth 20.04cm\oddsidemargin 0.0cm\evensidemargin 0.0cm
25 # Start symbols for the grammar:
26 # file_input is a module or sequence of commands read from an input file;
27 # single_input is a single interactive statement;
28 # eval_input is the input for the eval() and input() functions.
29 # NB: compound_stmt in single_input is followed by extra NEWLINE!
30 file_input: (NEWLINE | stmt)* ENDMARKER
31 single_input: NEWLINE | simple_stmt | compound_stmt NEWLINE
32 eval_input: testlist NEWLINE* ENDMARKER
34 decorator: '@' dotted_name [ '(' [arglist] ')' ] NEWLINE
35 decorators: decorator+
36 decorated: decorators (classdef | funcdef)
37 funcdef: 'def' NAME parameters ['->' test] ':' suite
38 parameters: '(' [typedargslist] ')'
39 typedargslist: ((tfpdef ['=' test] ',')*
40 ('*' [tname] (',' tname ['=' test])* [',' '**' tname] | '**' tname)
41 | tfpdef ['=' test] (',' tfpdef ['=' test])* [','])
42 tname: NAME [':' test]
43 tfpdef: tname | '(' tfplist ')'
44 tfplist: tfpdef (',' tfpdef)* [',']
45 varargslist: ((vfpdef ['=' test] ',')*
46 ('*' [vname] (',' vname ['=' test])* [',' '**' vname] | '**' vname)
47 | vfpdef ['=' test] (',' vfpdef ['=' test])* [','])
49 vfpdef: vname | '(' vfplist ')'
50 vfplist: vfpdef (',' vfpdef)* [',']
52 stmt: simple_stmt | compound_stmt
53 simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE
54 small_stmt: (expr_stmt | print_stmt | del_stmt | pass_stmt | flow_stmt |
55 import_stmt | global_stmt | exec_stmt | assert_stmt)
56 expr_stmt: testlist (augassign (yield_expr|testlist) |
57 ('=' (yield_expr|testlist))*)
58 augassign: ('+=' | '-=' | '*=' | '/=' | '%=' | '&=' | '|=' | '^=' |
59 '<<=' | '>>=' | '**=' | '//=')
60 # For normal assignments, additional restrictions enforced by the interpreter
61 print_stmt: 'print' ( [ test (',' test)* [','] ] |
62 '>>' test [ (',' test)+ [','] ] )
63 del_stmt: 'del' exprlist
65 flow_stmt: break_stmt | continue_stmt | return_stmt | raise_stmt | yield_stmt
67 continue_stmt: 'continue'
68 return_stmt: 'return' [testlist]
69 yield_stmt: yield_expr
70 raise_stmt: 'raise' [test ['from' test | ',' test [',' test]]]
71 import_stmt: import_name | import_from
72 import_name: 'import' dotted_as_names
73 import_from: ('from' ('.'* dotted_name | '.'+)
74 'import' ('*' | '(' import_as_names ')' | import_as_names))
75 import_as_name: NAME ['as' NAME]
76 dotted_as_name: dotted_name ['as' NAME]
77 import_as_names: import_as_name (',' import_as_name)* [',']
78 dotted_as_names: dotted_as_name (',' dotted_as_name)*
79 dotted_name: NAME ('.' NAME)*
80 global_stmt: ('global' | 'nonlocal') NAME (',' NAME)*
81 exec_stmt: 'exec' expr ['in' test [',' test]]
82 assert_stmt: 'assert' test [',' test]
84 compound_stmt: if_stmt | while_stmt | for_stmt | try_stmt | with_stmt | funcdef | classdef | decorated
85 if_stmt: 'if' test ':' suite ('elif' test ':' suite)* ['else' ':' suite]
86 while_stmt: 'while' test ':' suite ['else' ':' suite]
87 for_stmt: 'for' exprlist 'in' testlist ':' suite ['else' ':' suite]
88 try_stmt: ('try' ':' suite
89 ((except_clause ':' suite)+
91 ['finally' ':' suite] |
93 with_stmt: 'with' test [ with_var ] ':' suite
95 # NB compile.c makes sure that the default except clause is last
96 except_clause: 'except' [test [(',' | 'as') test]]
97 suite: simple_stmt | NEWLINE INDENT stmt+ DEDENT
99 # Backward compatibility cruft to support:
100 # [ x for x in lambda: True, lambda: False if x() ]
101 # even while also allowing:
102 # lambda x: 5 if x else 2
103 # (But not a mix of the two)
104 testlist_safe: old_test [(',' old_test)+ [',']]
105 old_test: or_test | old_lambdef
106 old_lambdef: 'lambda' [varargslist] ':' old_test
108 test: or_test ['if' or_test 'else' test] | lambdef
109 or_test: and_test ('or' and_test)*
110 and_test: not_test ('and' not_test)*
111 not_test: 'not' not_test | comparison
112 comparison: expr (comp_op expr)*
113 comp_op: '<'|'>'|'=='|'>='|'<='|'<>'|'!='|'in'|'not' 'in'|'is'|'is' 'not'
114 expr: xor_expr ('|' xor_expr)*
115 xor_expr: and_expr ('^' and_expr)*
116 and_expr: shift_expr ('&' shift_expr)*
117 shift_expr: arith_expr (('<<'|'>>') arith_expr)*
118 arith_expr: term (('+'|'-') term)*
119 term: factor (('*'|'/'|'%'|'//') factor)*
120 factor: ('+'|'-'|'~') factor | power
121 power: atom trailer* ['**' factor]
122 atom: ('(' [yield_expr|testlist_gexp] ')' |
123 '[' [listmaker] ']' |
124 '{' [dictsetmaker] '}' |
126 NAME | NUMBER | STRING+ | '.' '.' '.')
127 listmaker: test ( comp_for | (',' test)* [','] )
128 testlist_gexp: test ( comp_for | (',' test)* [','] )
129 lambdef: 'lambda' [varargslist] ':' test
130 trailer: '(' [arglist] ')' | '[' subscriptlist ']' | '.' NAME
131 subscriptlist: subscript (',' subscript)* [',']
132 subscript: test | [test] ':' [test] [sliceop]
134 exprlist: expr (',' expr)* [',']
135 testlist: test (',' test)* [',']
136 dictsetmaker: ( (test ':' test (comp_for | (',' test ':' test)* [','])) |
137 (test (comp_for | (',' test)* [','])) )
139 classdef: 'class' NAME ['(' [arglist] ')'] ':' suite
141 arglist: (argument ',')* (argument [',']
142 |'*' test (',' argument)* [',' '**' test]
144 argument: test [comp_for] | test '=' test # Really [keyword '='] test
146 comp_iter: comp_for | comp_if
147 comp_for: 'for' exprlist 'in' testlist_safe [comp_iter]
148 comp_if: 'if' old_test [comp_iter]
150 testlist1: test (',' test)*
152 # not used in grammar, but may appear in "node" passed from Parser to Compiler
155 yield_expr: 'yield' [testlist]