3 # NOTE WELL: You should also follow all the steps listed at
4 # https://docs.python.org/devguide/grammar.html
6 # Start symbols for the grammar:
7 # single_input is a single interactive statement;
8 # file_input is a module or sequence of commands read from an input file;
9 # eval_input is the input for the eval() functions.
10 # NB: compound_stmt in single_input is followed by extra NEWLINE!
11 single_input: NEWLINE | simple_stmt | compound_stmt NEWLINE
12 file_input: stmt* ENDMARKER
13 eval_input: testlist NEWLINE* ENDMARKER
14 decorator: '@' dotted_name [ '(' [arglist] ')' ] NEWLINE
15 decorators: decorator+
16 decorated: decorators (classdef | funcdef | async_funcdef)
18 # NOTE: Francisco Souza/Reinoud Elhorst, using ASYNC/'await' keywords instead of
19 # skipping python3.5+ compatibility, in favour of 3.7 solution
20 async_funcdef: 'async' funcdef
21 funcdef: 'def' NAME parameters ['->' test] ':' suite
23 parameters: '(' [typedargslist] ')'
24 typedargslist: (tfpdef ['=' test] (',' tfpdef ['=' test])* [',' [
25 '*' [tfpdef] (',' tfpdef ['=' test])* [',' ['**' tfpdef [',']]]
27 | '*' [tfpdef] (',' tfpdef ['=' test])* [',' ['**' tfpdef [',']]]
29 tfpdef: NAME [':' test]
30 varargslist: (vfpdef ['=' test] (',' vfpdef ['=' test])* [',' [
31 '*' [vfpdef] (',' vfpdef ['=' test])* [',' ['**' vfpdef [',']]]
33 | '*' [vfpdef] (',' vfpdef ['=' test])* [',' ['**' vfpdef [',']]]
38 stmt: simple_stmt | compound_stmt | NEWLINE
39 simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE
40 small_stmt: (expr_stmt | del_stmt | pass_stmt | flow_stmt |
41 import_stmt | global_stmt | nonlocal_stmt | assert_stmt)
42 expr_stmt: testlist_star_expr (annassign | augassign (yield_expr|testlist) |
43 ('=' (yield_expr|testlist_star_expr))*)
44 annassign: ':' test ['=' test]
45 testlist_star_expr: (test|star_expr) (',' (test|star_expr))* [',']
46 augassign: ('+=' | '-=' | '*=' | '@=' | '/=' | '%=' | '&=' | '|=' | '^=' |
47 '<<=' | '>>=' | '**=' | '//=')
48 # For normal and annotated assignments, additional restrictions enforced by the interpreter
49 del_stmt: 'del' exprlist
51 flow_stmt: break_stmt | continue_stmt | return_stmt | raise_stmt | yield_stmt
53 continue_stmt: 'continue'
54 return_stmt: 'return' [testlist]
55 yield_stmt: yield_expr
56 raise_stmt: 'raise' [test ['from' test]]
57 import_stmt: import_name | import_from
58 import_name: 'import' dotted_as_names
59 # note below: the ('.' | '...') is necessary because '...' is tokenized as ELLIPSIS
60 import_from: ('from' (('.' | '...')* dotted_name | ('.' | '...')+)
61 'import' ('*' | '(' import_as_names ')' | import_as_names))
62 import_as_name: NAME ['as' NAME]
63 dotted_as_name: dotted_name ['as' NAME]
64 import_as_names: import_as_name (',' import_as_name)* [',']
65 dotted_as_names: dotted_as_name (',' dotted_as_name)*
66 dotted_name: NAME ('.' NAME)*
67 global_stmt: 'global' NAME (',' NAME)*
68 nonlocal_stmt: 'nonlocal' NAME (',' NAME)*
69 assert_stmt: 'assert' test [',' test]
71 compound_stmt: if_stmt | while_stmt | for_stmt | try_stmt | with_stmt | funcdef | classdef | decorated | async_stmt
72 async_stmt: 'async' (funcdef | with_stmt | for_stmt)
73 if_stmt: 'if' test ':' suite ('elif' test ':' suite)* ['else' ':' suite]
74 while_stmt: 'while' test ':' suite ['else' ':' suite]
75 for_stmt: 'for' exprlist 'in' testlist ':' suite ['else' ':' suite]
76 try_stmt: ('try' ':' suite
77 ((except_clause ':' suite)+
79 ['finally' ':' suite] |
81 with_stmt: 'with' with_item (',' with_item)* ':' suite
82 with_item: test ['as' expr]
83 # NB compile.c makes sure that the default except clause is last
84 except_clause: 'except' [test ['as' NAME]]
85 suite: simple_stmt | NEWLINE INDENT stmt+ DEDENT
87 test: or_test ['if' or_test 'else' test] | lambdef
88 test_nocond: or_test | lambdef_nocond
89 lambdef: 'lambda' [varargslist] ':' test
90 lambdef_nocond: 'lambda' [varargslist] ':' test_nocond
91 or_test: and_test ('or' and_test)*
92 and_test: not_test ('and' not_test)*
93 not_test: 'not' not_test | comparison
94 comparison: expr (comp_op expr)*
95 # <> isn't actually a valid comparison operator in Python. It's here for the
96 # sake of a __future__ import described in PEP 401 (which really works :-)
97 comp_op: '<'|'>'|'=='|'>='|'<='|'<>'|'!='|'in'|'not' 'in'|'is'|'is' 'not'
99 expr: xor_expr ('|' xor_expr)*
100 xor_expr: and_expr ('^' and_expr)*
101 and_expr: shift_expr ('&' shift_expr)*
102 shift_expr: arith_expr (('<<'|'>>') arith_expr)*
103 arith_expr: term (('+'|'-') term)*
104 term: factor (('*'|'@'|'/'|'%'|'//') factor)*
105 factor: ('+'|'-'|'~') factor | power
106 power: atom_expr ['**' factor]
107 atom_expr: ['await'] atom trailer*
108 atom: ('(' [yield_expr|testlist_comp] ')' |
109 '[' [testlist_comp] ']' |
110 '{' [dictorsetmaker] '}' |
111 NAME | NUMBER | strings | '...' | 'None' | 'True' | 'False')
112 testlist_comp: (test|star_expr) ( comp_for | (',' (test|star_expr))* [','] )
113 trailer: '(' [arglist] ')' | '[' subscriptlist ']' | '.' NAME
114 subscriptlist: subscript (',' subscript)* [',']
115 subscript: test | [test] ':' [test] [sliceop]
117 exprlist: (expr|star_expr) (',' (expr|star_expr))* [',']
118 testlist: test (',' test)* [',']
119 dictorsetmaker: ( ((test ':' test | '**' expr)
120 (comp_for | (',' (test ':' test | '**' expr))* [','])) |
122 (comp_for | (',' (test | star_expr))* [','])) )
124 classdef: 'class' NAME ['(' [arglist] ')'] ':' suite
126 arglist: argument (',' argument)* [',']
128 # The reason that keywords are test nodes instead of NAME is that using NAME
129 # results in an ambiguity. ast.c makes sure it's a NAME.
130 # "test '=' test" is really "keyword '=' test", but we have no such token.
131 # These need to be in a single rule to avoid grammar that is ambiguous
132 # to our LL(1) parser. Even though 'test' includes '*expr' in star_expr,
133 # we explicitly match '*' here, too, to give it proper precedence.
134 # Illegal combinations and orderings are blocked in ast.c:
135 # multiple (test comp_for) arguments are blocked; keyword unpackings
136 # that precede iterable unpackings are blocked; etc.
137 argument: ( test [comp_for] |
142 comp_iter: comp_for | comp_if
143 sync_comp_for: 'for' exprlist 'in' or_test [comp_iter]
144 comp_for: ['async'] sync_comp_for
145 comp_if: 'if' test_nocond [comp_iter]
147 # not used in grammar, but may appear in "node" passed from Parser to Compiler
150 yield_expr: 'yield' [yield_arg]
151 yield_arg: 'from' test | testlist
153 strings: (STRING | fstring)+
154 fstring: FSTRING_START fstring_content* FSTRING_END
155 fstring_content: FSTRING_STRING | fstring_expr
156 fstring_conversion: '!' NAME
157 fstring_expr: '{' (testlist_comp | yield_expr) [ fstring_conversion ] [ fstring_format_spec ] '}'
158 fstring_format_spec: ':' fstring_content*