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grammar SimpleCalc;
options { language = Perl5; }
tokens {
PLUS = '+' ;
MINUS = '-' ;
MULT = '*' ;
DIV = '/' ;
}
/*------------------------------------------------------------------
* PARSER RULES
*------------------------------------------------------------------*/
expr : term ( ( PLUS | MINUS ) term )* ;
term : factor ( ( MULT | DIV ) factor )* ;
factor : NUMBER ;
/*------------------------------------------------------------------
* LEXER RULES
*------------------------------------------------------------------*/
NUMBER : (DIGIT)+ ;
WHITESPACE : ( '\t' | ' ' | '\r' | '\n'| '\u000C' )+ { $channel = $self->HIDDEN; } ;
fragment DIGIT : '0'..'9' ;
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