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grammar t047treeparser;
options {
language=Python3;
output=AST;
}
tokens {
VAR_DEF;
ARG_DEF;
FUNC_HDR;
FUNC_DECL;
FUNC_DEF;
BLOCK;
}
program
: declaration+
;
declaration
: variable
| functionHeader ';' -> ^(FUNC_DECL functionHeader)
| functionHeader block -> ^(FUNC_DEF functionHeader block)
;
variable
: type declarator ';' -> ^(VAR_DEF type declarator)
;
declarator
: ID
;
functionHeader
: type ID '(' ( formalParameter ( ',' formalParameter )* )? ')'
-> ^(FUNC_HDR type ID formalParameter+)
;
formalParameter
: type declarator -> ^(ARG_DEF type declarator)
;
type
: 'int'
| 'char'
| 'void'
| ID
;
block
: lc='{'
variable*
stat*
'}'
-> ^(BLOCK[$lc,"BLOCK"] variable* stat*)
;
stat: forStat
| expr ';'!
| block
| assignStat ';'!
| ';'!
;
forStat
: 'for' '(' start=assignStat ';' expr ';' next=assignStat ')' block
-> ^('for' $start expr $next block)
;
assignStat
: ID EQ expr -> ^(EQ ID expr)
;
expr: condExpr
;
condExpr
: aexpr ( ('=='^ | '<'^) aexpr )?
;
aexpr
: atom ( '+'^ atom )*
;
atom
: ID
| INT
| '(' expr ')' -> expr
;
FOR : 'for' ;
INT_TYPE : 'int' ;
CHAR: 'char';
VOID: 'void';
ID : ('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'0'..'9'|'_')*
;
INT : ('0'..'9')+
;
EQ : '=' ;
EQEQ : '==' ;
LT : '<' ;
PLUS : '+' ;
WS : ( ' '
| '\t'
| '\r'
| '\n'
)+
{ $channel=HIDDEN }
;