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