# Grammar for Python | |
# Note: Changing the grammar specified in this file will most likely | |
# require corresponding changes in the parser module | |
# (../Modules/parsermodule.c). If you can't make the changes to | |
# that module yourself, please co-ordinate the required changes | |
# with someone who can; ask around on python-dev for help. Fred | |
# Drake <fdrake@acm.org> will probably be listening there. | |
# NOTE WELL: You should also follow all the steps listed in PEP 306, | |
# "How to Change Python's Grammar" | |
# Commands for Kees Blom's railroad program | |
#diagram:token NAME | |
#diagram:token NUMBER | |
#diagram:token STRING | |
#diagram:token NEWLINE | |
#diagram:token ENDMARKER | |
#diagram:token INDENT | |
#diagram:output\input python.bla | |
#diagram:token DEDENT | |
#diagram:output\textwidth 20.04cm\oddsidemargin 0.0cm\evensidemargin 0.0cm | |
#diagram:rules | |
# Start symbols for the grammar: | |
# file_input is a module or sequence of commands read from an input file; | |
# single_input is a single interactive statement; | |
# eval_input is the input for the eval() and input() functions. | |
# NB: compound_stmt in single_input is followed by extra NEWLINE! | |
file_input: (NEWLINE | stmt)* ENDMARKER | |
single_input: NEWLINE | simple_stmt | compound_stmt NEWLINE | |
eval_input: testlist NEWLINE* ENDMARKER | |
decorator: '@' dotted_name [ '(' [arglist] ')' ] NEWLINE | |
decorators: decorator+ | |
decorated: decorators (classdef | funcdef) | |
funcdef: 'def' NAME parameters ['->' test] ':' suite | |
parameters: '(' [typedargslist] ')' | |
typedargslist: ((tfpdef ['=' test] ',')* | |
('*' [tname] (',' tname ['=' test])* [',' '**' tname] | '**' tname) | |
| tfpdef ['=' test] (',' tfpdef ['=' test])* [',']) | |
tname: NAME [':' test] | |
tfpdef: tname | '(' tfplist ')' | |
tfplist: tfpdef (',' tfpdef)* [','] | |
varargslist: ((vfpdef ['=' test] ',')* | |
('*' [vname] (',' vname ['=' test])* [',' '**' vname] | '**' vname) | |
| vfpdef ['=' test] (',' vfpdef ['=' test])* [',']) | |
vname: NAME | |
vfpdef: vname | '(' vfplist ')' | |
vfplist: vfpdef (',' vfpdef)* [','] | |
stmt: simple_stmt | compound_stmt | |
simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE | |
small_stmt: (expr_stmt | print_stmt | del_stmt | pass_stmt | flow_stmt | | |
import_stmt | global_stmt | exec_stmt | assert_stmt) | |
expr_stmt: testlist_star_expr (augassign (yield_expr|testlist) | | |
('=' (yield_expr|testlist_star_expr))*) | |
testlist_star_expr: (test|star_expr) (',' (test|star_expr))* [','] | |
augassign: ('+=' | '-=' | '*=' | '/=' | '%=' | '&=' | '|=' | '^=' | | |
'<<=' | '>>=' | '**=' | '//=') | |
# For normal assignments, additional restrictions enforced by the interpreter | |
print_stmt: 'print' ( [ test (',' test)* [','] ] | | |
'>>' test [ (',' test)+ [','] ] ) | |
del_stmt: 'del' exprlist | |
pass_stmt: 'pass' | |
flow_stmt: break_stmt | continue_stmt | return_stmt | raise_stmt | yield_stmt | |
break_stmt: 'break' | |
continue_stmt: 'continue' | |
return_stmt: 'return' [testlist] | |
yield_stmt: yield_expr | |
raise_stmt: 'raise' [test ['from' test | ',' test [',' test]]] | |
import_stmt: import_name | import_from | |
import_name: 'import' dotted_as_names | |
import_from: ('from' ('.'* dotted_name | '.'+) | |
'import' ('*' | '(' import_as_names ')' | import_as_names)) | |
import_as_name: NAME ['as' NAME] | |
dotted_as_name: dotted_name ['as' NAME] | |
import_as_names: import_as_name (',' import_as_name)* [','] | |
dotted_as_names: dotted_as_name (',' dotted_as_name)* | |
dotted_name: NAME ('.' NAME)* | |
global_stmt: ('global' | 'nonlocal') NAME (',' NAME)* | |
exec_stmt: 'exec' expr ['in' test [',' test]] | |
assert_stmt: 'assert' test [',' test] | |
compound_stmt: if_stmt | while_stmt | for_stmt | try_stmt | with_stmt | funcdef | classdef | decorated | |
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] | |
with_var: 'as' expr | |
# NB compile.c makes sure that the default except clause is last | |
except_clause: 'except' [test [(',' | 'as') test]] | |
suite: simple_stmt | NEWLINE INDENT stmt+ DEDENT | |
# Backward compatibility cruft to support: | |
# [ x for x in lambda: True, lambda: False if x() ] | |
# even while also allowing: | |
# lambda x: 5 if x else 2 | |
# (But not a mix of the two) | |
testlist_safe: old_test [(',' old_test)+ [',']] | |
old_test: or_test | old_lambdef | |
old_lambdef: 'lambda' [varargslist] ':' old_test | |
test: or_test ['if' or_test 'else' test] | lambdef | |
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)* | |
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 trailer* ['**' factor] | |
atom: ('(' [yield_expr|testlist_gexp] ')' | | |
'[' [listmaker] ']' | | |
'{' [dictsetmaker] '}' | | |
'`' testlist1 '`' | | |
NAME | NUMBER | STRING+ | '.' '.' '.') | |
listmaker: (test|star_expr) ( comp_for | (',' (test|star_expr))* [','] ) | |
testlist_gexp: (test|star_expr) ( comp_for | (',' (test|star_expr))* [','] ) | |
lambdef: 'lambda' [varargslist] ':' test | |
trailer: '(' [arglist] ')' | '[' subscriptlist ']' | '.' NAME | |
subscriptlist: subscript (',' subscript)* [','] | |
subscript: test | [test] ':' [test] [sliceop] | |
sliceop: ':' [test] | |
exprlist: (expr|star_expr) (',' (expr|star_expr))* [','] | |
testlist: test (',' test)* [','] | |
dictsetmaker: ( (test ':' test (comp_for | (',' test ':' test)* [','])) | | |
(test (comp_for | (',' test)* [','])) ) | |
classdef: 'class' NAME ['(' [arglist] ')'] ':' suite | |
arglist: (argument ',')* (argument [','] | |
|'*' test (',' argument)* [',' '**' test] | |
|'**' test) | |
argument: test [comp_for] | test '=' test # Really [keyword '='] test | |
comp_iter: comp_for | comp_if | |
comp_for: 'for' exprlist 'in' testlist_safe [comp_iter] | |
comp_if: 'if' old_test [comp_iter] | |
testlist1: test (',' test)* | |
# not used in grammar, but may appear in "node" passed from Parser to Compiler | |
encoding_decl: NAME | |
yield_expr: 'yield' [testlist] |