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 # single_input is a single interactive statement;
27 # file_input is a module or sequence of commands read from an input file;
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 single_input: NEWLINE | simple_stmt | compound_stmt NEWLINE
31 file_input: (NEWLINE | stmt)* ENDMARKER
32 eval_input: testlist NEWLINE* ENDMARKER
34 decorator: '@' dotted_name [ '(' [arglist] ')' ] NEWLINE
35 decorators: decorator+
36 funcdef: [decorators] 'def' NAME parameters ':' suite
37 parameters: '(' [varargslist] ')'
38 varargslist: ((fpdef ['=' test] ',')*
39 ('*' NAME [',' '**' NAME] | '**' NAME) |
40 fpdef ['=' test] (',' fpdef ['=' test])* [','])
41 fpdef: NAME | '(' fplist ')'
42 fplist: fpdef (',' fpdef)* [',']
44 stmt: simple_stmt | compound_stmt
45 simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE
46 small_stmt: (expr_stmt | print_stmt | del_stmt | pass_stmt | flow_stmt |
47 import_stmt | global_stmt | exec_stmt | assert_stmt)
48 expr_stmt: testlist (augassign (yield_expr|testlist) |
49 ('=' (yield_expr|testlist))*)
50 augassign: ('+=' | '-=' | '*=' | '/=' | '%=' | '&=' | '|=' | '^=' |
51 '<<=' | '>>=' | '**=' | '//=')
52 # For normal assignments, additional restrictions enforced by the interpreter
53 print_stmt: 'print' ( [ test (',' test)* [','] ] |
54 '>>' test [ (',' test)+ [','] ] )
55 del_stmt: 'del' exprlist
57 flow_stmt: break_stmt | continue_stmt | return_stmt | raise_stmt | yield_stmt
59 continue_stmt: 'continue'
60 return_stmt: 'return' [testlist]
61 yield_stmt: yield_expr
62 raise_stmt: 'raise' [test [',' test [',' test]]]
63 import_stmt: import_name | import_from
64 import_name: 'import' dotted_as_names
65 import_from: ('from' ('.'* dotted_name | '.'+)
66 'import' ('*' | '(' import_as_names ')' | import_as_names))
67 import_as_name: NAME ['as' NAME]
68 dotted_as_name: dotted_name ['as' NAME]
69 import_as_names: import_as_name (',' import_as_name)* [',']
70 dotted_as_names: dotted_as_name (',' dotted_as_name)*
71 dotted_name: NAME ('.' NAME)*
72 global_stmt: 'global' NAME (',' NAME)*
73 exec_stmt: 'exec' expr ['in' test [',' test]]
74 assert_stmt: 'assert' test [',' test]
76 compound_stmt: if_stmt | while_stmt | for_stmt | try_stmt | with_stmt | funcdef | classdef
77 if_stmt: 'if' test ':' suite ('elif' test ':' suite)* ['else' ':' suite]
78 while_stmt: 'while' test ':' suite ['else' ':' suite]
79 for_stmt: 'for' exprlist 'in' testlist ':' suite ['else' ':' suite]
80 try_stmt: ('try' ':' suite
81 ((except_clause ':' suite)+
83 ['finally' ':' suite] |
85 with_stmt: 'with' test [ with_var ] ':' suite
87 # NB compile.c makes sure that the default except clause is last
88 except_clause: 'except' [test [('as' | ',') test]]
89 suite: simple_stmt | NEWLINE INDENT stmt+ DEDENT
91 # Backward compatibility cruft to support:
92 # [ x for x in lambda: True, lambda: False if x() ]
93 # even while also allowing:
94 # lambda x: 5 if x else 2
95 # (But not a mix of the two)
96 testlist_safe: old_test [(',' old_test)+ [',']]
97 old_test: or_test | old_lambdef
98 old_lambdef: 'lambda' [varargslist] ':' old_test
100 test: or_test ['if' or_test 'else' test] | lambdef
101 or_test: and_test ('or' and_test)*
102 and_test: not_test ('and' not_test)*
103 not_test: 'not' not_test | comparison
104 comparison: expr (comp_op expr)*
105 comp_op: '<'|'>'|'=='|'>='|'<='|'<>'|'!='|'in'|'not' 'in'|'is'|'is' 'not'
106 expr: xor_expr ('|' xor_expr)*
107 xor_expr: and_expr ('^' and_expr)*
108 and_expr: shift_expr ('&' shift_expr)*
109 shift_expr: arith_expr (('<<'|'>>') arith_expr)*
110 arith_expr: term (('+'|'-') term)*
111 term: factor (('*'|'/'|'%'|'//') factor)*
112 factor: ('+'|'-'|'~') factor | power
113 power: atom trailer* ['**' factor]
114 atom: ('(' [yield_expr|testlist_gexp] ')' |
115 '[' [listmaker] ']' |
116 '{' [dictmaker] '}' |
118 NAME | NUMBER | STRING+)
119 listmaker: test ( list_for | (',' test)* [','] )
120 testlist_gexp: test ( gen_for | (',' test)* [','] )
121 lambdef: 'lambda' [varargslist] ':' test
122 trailer: '(' [arglist] ')' | '[' subscriptlist ']' | '.' NAME
123 subscriptlist: subscript (',' subscript)* [',']
124 subscript: '.' '.' '.' | test | [test] ':' [test] [sliceop]
126 exprlist: expr (',' expr)* [',']
127 testlist: test (',' test)* [',']
128 dictmaker: test ':' test (',' test ':' test)* [',']
130 classdef: 'class' NAME ['(' [testlist] ')'] ':' suite
132 arglist: (argument ',')* (argument [',']| '*' test [',' '**' test] | '**' test)
133 argument: test [gen_for] | test '=' test # Really [keyword '='] test
135 list_iter: list_for | list_if
136 list_for: 'for' exprlist 'in' testlist_safe [list_iter]
137 list_if: 'if' old_test [list_iter]
139 gen_iter: gen_for | gen_if
140 gen_for: 'for' exprlist 'in' or_test [gen_iter]
141 gen_if: 'if' old_test [gen_iter]
143 testlist1: test (',' test)*
145 # not used in grammar, but may appear in "node" passed from Parser to Compiler
148 yield_expr: 'yield' [testlist]