// Based on https://docs.python.org/2.7/reference/grammar.html
// with some modifications.

token Lt='<' Gt='>' Eq='=' At='@' And='&' Dot='.' LPar='(' RPar=')'
      Star='*' Plus='+' Semi=';' Lt2='<<' Eq2='==' Gt2='>>' Pipe='|'
      Comma=',' Minus='-' Slash='/' Colon=':' LtEq='<=' LtGt='<>'
      GtEq='>=' LBrak='[' RBrak=']' Caret='^' BTick='`' Tilde='~'
      AndEq='&=' Star2='**' LBrace='{' RBrace='}' ExclEq='!='
      Percent='%' StarEq='*=' PlusEq='+=' Slash2='//' Lt2Eq='<<='
      Gt2Eq='>>=' PipeEq='|=' MinusEq='-=' SlashEq='/=' CaretEq='^='
      Star2Eq='**=' PercentEq='%=' Slash2Eq='//=';
token As='as' If='if' In='in' Is='is' Or='or' AndKw='and' Def='def'
      Del='del' For='for' Not='not' Try='try' Else='else' Exec='exec'
      From='from' Pass='pass' Elif='elif' With='with' Break='break'
      Class='class' Print='print' Raise='raise' While='while'
      Assert='assert' Except='except' Global='global' Import='import'
      Lambda='lambda' Return='return' Finally='finally' Continue='continue'
      Yield='yield';
token Newline Name Dedent Indent Int Float Imaginary String;
token Whitespace Comment;

skip Whitespace Comment;
right '**';

start file_input;
part single_input eval_input;

/// a module or sequence of commands read from an input file
file_input: (Newline | stmt)*;
/// a single interactive statement
single_input: Newline | simple_stmts | compound_stmt Newline;
/// the input for the eval() and input() functions
eval_input: testlist Newline*;

decorator: '@' dotted_name [ '(' [arglist] ')' ] Newline;
decorators: decorator+;
decorated: decorators (classdef | funcdef);
funcdef: 'def' Name parameters ':' suite;
parameters: '(' [varargslist] ')';
varargslist:
  fpdef ['=' test] (?1 ',' fpdef ['=' test])* [',' ['*' Name [',' '**' Name] | '**' Name]]
| '*' Name [',' '**' Name]
| '**' Name
;
fpdef: Name | '(' fplist ')';
fplist: fpdef (?1 ',' fpdef)* [','];

stmt^: simple_stmts | compound_stmt;
simple_stmts: small_stmt (?1 ';' 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 (
    augassign (yield_expr | testlist) @aug_assign_stmt
  | ('=' (yield_expr | testlist))* @assign_stmt
  )
;
augassign^:
  '+=' | '-=' | '*=' | '/=' | '%=' | '&=' | '|=' | '^=' | '<<=' | '>>=' | '**=' | '//='
;
print_stmt:
  'print' (
    [ test (?1 ',' test)* [','] ]
  | '>>' test [ (?1 ',' 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 [',' test [',' test]]];
import_stmt: import_name | import_from;
import_name: 'import' dotted_as_names;
import_from:
  'from' ('.'+ [dotted_name] | 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 (?1 ',' import_as_name)* [','];
dotted_as_names: dotted_as_name (',' dotted_as_name)*;
dotted_name: Name ('.' Name)*;
global_stmt: 'global' 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];
except_clause: 'except' [test [('as' | ',') test]];
suite: simple_stmts | Newline Indent stmt+ Dedent;

testlist_safe: old_test [(?1 ',' old_test)+ [',']];
old_test: or_test | old_lambdef;
old_lambdef: 'lambda' [varargslist] ':' old_test;

test^:
  or_test ['if' or_test 'else' test >if_expr]
| lambda_expr;
or_test:
  'not' or_test @unary_expr
| or_test 'and' or_test @bool_expr
| or_test 'or' or_test @bool_expr
| ^ <1 expr [(comp_op expr)+ 1>compare_expr]
;
comp_op^: '<' | '>' | '==' | '>=' | '<=' | '<>' | '!=' | 'in' | 'not' 'in' | 'is' ['not'];
expr:
  expr '**' expr @binary_expr
| expr '(' [arglist] ')' @call_expr
| expr '[' subscriptlist ']' @subscript_expr
| expr '.' Name @field_expr
| ('+'|'-'|'~') expr @unary_expr
| expr ('*' | '/' | '%' | '//') expr @binary_expr
| expr ('+' | '-') expr @binary_expr
| expr ('<<' | '>>') expr @binary_expr
| expr '&' expr @binary_expr
| expr '^' expr @binary_expr
| expr '|' expr @binary_expr
| '(' [yield_expr | testlist_comp] ')' @tuple_expr
| '[' [listmaker] ']' @list_expr
| '{' [dictorsetmaker] '}' @dict_expr
| '`' testlist1 '`' @repr_expr
| Name @name_expr
| Int @int_expr
| Float @float_expr
| Imaginary @imaginary_expr
| String+ @string_expr
;
listmaker: test (list_for | (?1 ',' test)* [',']);
testlist_comp: test (comp_for | (?1 ',' test)* [',']);
lambda_expr: 'lambda' [varargslist] ':' test;
subscriptlist: subscript (?1 ',' subscript)* [','];
subscript:
  '.' '.' '.'
| test [':' [test] [sliceop]]
| ':' [test] [sliceop]
;
sliceop: ':' [test];
exprlist: expr (?1 ',' expr)* [','];
testlist: test (?1 ',' test)* [','];
dictorsetmaker:
  test (
    ':' test (comp_for | (?1 ',' test ':' test)* [','])
  | (comp_for | (?1 ',' test)* [','])
  )
;
classdef: 'class' Name ['(' [testlist] ')'] ':' suite;

arglist:
  argument (?1 ',' argument)* [
    ',' [
      '*' test (?2 ',' argument)* [',' '**' test]
    | '**' test
    ]
  ]
| '*' test (?2 ',' argument)* [',' '**' test]
| '**' test
;
argument: test [comp_for | '=' test];

list_iter: list_for | list_if;
list_for: 'for' exprlist 'in' testlist_safe [list_iter];
list_if: 'if' old_test [list_iter];

comp_iter: comp_for | comp_if;
comp_for: 'for' exprlist 'in' or_test [comp_iter];
comp_if: 'if' old_test [comp_iter];

testlist1: test (',' test)*;

yield_expr: 'yield' [testlist];