SimpleCalcWalker.g

tree grammar SimpleCalcWalker;

options {
    language=JavaScript;
    tokenVocab=SimpleCalc;
    ASTLabelType=CommonTree;
}

eval returns [var result]
    : e=math EOF { result = e; }
    ;

math returns [var result]
    : ^('+' op1=math op2=math) { result = op1 + op2; }
    | ^('-' op1=math op2=math) { result = op1 - op2; }
    | ^('*' op1=math op2=math) { result = op1 * op2; }
    | ^('/' op1=math op2=math) { result = op1 / op2; }
    | ^('%' op1=math op2=math) { result = op1 \% op2; }
    | ^(NEGATION op1=math) { result = -op1; }
    | FLOAT { result = parseFloat($FLOAT.text); }
    | INT { result = parseInt($INT.text); }
    ;