内建函数

• print
• int
• float
• str
• bool

表达式解析

• file_input: (NEWLINE | stmt)* EOF;

• funcdef: 'def' NAME parameters ':' suite;

• parameters: '(' typedargslist? ')';

• typedargslist: (tfpdef ('=' test)? (',' tfpdef ('=' test)?)*);

• tfpdef: NAME ;

• stmt: simple_stmt | compound_stmt;

• simple_stmt: small_stmt NEWLINE;

• small_stmt: expr_stmt | flow_stmt;

• expr_stmt: testlist ( (augassign testlist) | ('=' testlist)*);

• augassign: ('+=' | '-=' | '*=' | '/=' | '//=' | '%=' );

• flow_stmt: break_stmt | continue_stmt | return_stmt;

• break_stmt: 'break';

• continue_stmt: 'continue';

• return_stmt: 'return' (testlist)?;

• compound_stmt: if_stmt | while_stmt | funcdef ;

• if_stmt: 'if' test ':' suite ('elif' test ':' suite)* ('else' ':' suite)?;

• while_stmt: 'while' test ':' suite;

• suite: simple_stmt | NEWLINE INDENT stmt+ DEDENT;

• test: or_test ;

• or_test: and_test ('or' and_test)*;

• and_test: not_test ('and' not_test)*;

• not_test: 'not' not_test | comparison;

• comparison: arith_expr (comp_op arith_expr)*;

• comp_op: '<'|'>'|'=='|'>='|'<=' | '!=';

• arith_expr: term (addorsub_op term)*;

• addorsub_op: '+'|'-';

• term: factor (muldivmod_op factor)*;

• muldivmod_op: '*'|'/'|'//'|'%';

• factor: ('+'|'-') factor | atom_expr;

• atom_expr: atom trailer?;

• trailer: '(' (arglist)? ')' ;

• atom: (NAME | NUMBER | STRING+| 'None' | 'True' | 'False' | ('(' test ')'));

• testlist: test (',' test)* (',')?;

• arglist: argument (',' argument)* (',')?;

• argument: ( test | test '=' test );