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这是完整的Python语法,因为它由解析器生成器读取并用于解析Python源文件:

# Grammar for Python 
# NOTE WELL: You should also follow all the steps listed at 
# https://devguide.python.org/grammar/ 
# Start symbols for the grammar: 
# single_input is a single interactive statement; 
# file_input is a module or sequence of commands read from an input file; 
# eval_input is the input for the eval() functions. 
# NB: compound_stmt in single_input is followed by extra NEWLINE! 

single_input: NEWLINE | simple_stmt | compound_stmt NEWLINE 
file_input: (NEWLINE | stmt)* ENDMARKER 
eval_input: testlist NEWLINE* ENDMARKER 

decorator: '@' dotted_name [ '(' [arglist] ')' ] NEWLINE 
decorators: decorator+ 
decorated: decorators (classdef | funcdef | async_funcdef) 

async_funcdef: 'async' funcdef 
funcdef: 'def' NAME parameters ['->' test] ':' suite 

parameters: '(' [typedargslist] ')' 
typedargslist: (tfpdef ['=' test] (',' tfpdef ['=' test])* [',' [
    '*' [tfpdef] (',' tfpdef ['=' test])* [',' ['**' tfpdef [',']]]
    | '**' tfpdef [',']]] 
    | '*' [tfpdef] (',' tfpdef ['=' test])* [',' ['**' tfpdef [',']]] 
    | '**' tfpdef [',']) 
tfpdef: NAME [':' test] 
varargslist: (vfpdef ['=' test] (',' vfpdef ['=' test])* [',' [ 
    '*' [vfpdef] (',' vfpdef ['=' test])* [',' ['**' vfpdef [',']]] 
    | '**' vfpdef [',']]] 
    | '*' [vfpdef] (',' vfpdef ['=' test])* [',' ['**' vfpdef [',']]] 
    | '**' vfpdef [','] ) 
vfpdef: NAME 
stmt: simple_stmt | compound_stmt 
simple_stmt: small_stmt (';' small_stmt)* [';'] NEWLINE 
small_stmt: (expr_stmt | del_stmt | pass_stmt | flow_stmt | import_stmt | global_stmt | nonlocal_stmt | assert_stmt) 
expr_stmt: testlist_star_expr (annassign | augassign (yield_expr|testlist)  | ('=' (yield_expr|testlist_star_expr))*) 
annassign: ':' test ['=' test] 
testlist_star_expr: (test|star_expr) (',' (test|star_expr))* [','] 
augassign: ('+=' | '-=' | '*=' | '@=' | '/=' | '%=' | '&=' | '|=' | '^=' | '<<=' | '>>=' | '**=' | '//=') 
# For normal and annotated assignments, additional restrictions enforced by the interpreter 
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]] 
import_stmt: import_name | import_from 
import_name: 'import' dotted_as_names 
# note below: the ('.' | '...') is necessary because '...' is tokenized as ELLIPSIS 
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' NAME (',' NAME)* 
nonlocal_stmt: 'nonlocal' NAME (',' NAME)* 
assert_stmt: 'assert' test [',' test] 
compound_stmt: if_stmt | while_stmt | for_stmt | try_stmt | with_stmt | funcdef | classdef | decorated | async_stmt 
async_stmt: 'async' (funcdef | with_stmt | for_stmt) 
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] # NB compile.c makes sure that the default except clause is last 
except_clause: 'except' [test ['as' NAME]] 
suite: simple_stmt | NEWLINE INDENT stmt+ DEDENT 
test: or_test ['if' or_test 'else' test] | lambdef 
test_nocond: or_test | lambdef_nocond 
lambdef: 'lambda' [varargslist] ':' test 
lambdef_nocond: 'lambda' [varargslist] ':' test_nocond 
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)* 
# <> isn't actually a valid comparison operator in Python. It's here for the 
# sake of a __future__ import described in PEP 401 (which really works :-) 
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_expr ['**' factor] 
atom_expr: ['await'] atom trailer* 
atom: ('(' [yield_expr|testlist_comp] ')' | '[' [testlist_comp] ']' | '{' [dictorsetmaker] '}' | NAME | NUMBER | STRING+ | '...' | 'None' | 'True' | 'False') 
testlist_comp: (test|star_expr) ( comp_for | (',' (test|star_expr))* [','] ) 
trailer: '(' [arglist] ')' | '[' subscriptlist ']' | '.' 
NAME subscriptlist: subscript (',' subscript)* [','] 
subscript: test | [test] ':' [test] [sliceop]
sliceop: ':' [test] 
exprlist: (expr|star_expr) (',' (expr|star_expr))* [','] 
testlist: test (',' test)* [','] 
dictorsetmaker: ( ((test ':' test | '**' expr) (comp_for | (',' (test ':' test | '**' expr))* [','])) | ((test | star_expr) (comp_for | (',' (test | star_expr))* [','])) ) 
classdef: 'class' NAME ['(' [arglist] ')'] ':' suite 
arglist: argument (',' argument)* [','] 
# The reason that keywords are test nodes instead of NAME is that using NAME 
# results in an ambiguity. ast.c makes sure it's a NAME. 
# "test '=' test" is really "keyword '=' test", but we have no such token. 
# These need to be in a single rule to avoid grammar that is ambiguous 
# to our LL(1) parser. Even though 'test' includes '*expr' in star_expr, 
# we explicitly match '*' here, too, to give it proper precedence. 
# Illegal combinations and orderings are blocked in ast.c: 
# multiple (test comp_for) arguments are blocked; keyword unpackings 
# that precede iterable unpackings are blocked; etc. 
argument: ( test [comp_for] | test '=' test | '**' test | '*' test ) 
comp_iter: comp_for | comp_if 
sync_comp_for: 'for' exprlist 'in' or_test [comp_iter] 
comp_for: ['async'] sync_comp_for 
comp_if: 'if' test_nocond [comp_iter] 
# not used in grammar, but may appear in "node" passed from Parser to Compiler 
encoding_decl: NAME 
yield_expr: 'yield' [yield_arg] 
yield_arg: 'from' test | testlist