SimpleCalc.g

grammar SimpleCalc;

options {
    language=JavaScript;
    output=AST;
    ASTLabelType=CommonTree;
}

tokens {
    NEGATION;
}

evaluate
    : math EOF
    ;
math
    : term (('+' | '-')^ term)* 
    ;
term
    : unary (('*' | '/' | '%')^ unary)*
    ;
unary
    : ('+'! | negation^)* factor
    ;
negation
    : '-' -> NEGATION
    ;
factor
    : FLOAT
    | INT
    | IDENT
    | '('! math ')'!

IDENT: ('a'..'z' | 'A'..'Z')('a'..'z' | 'A'..'Z' | '0'..'9' | '_')*;
FLOAT: ('0'..'9'+ '.' '0'..'9'+) | ('0'..'9' '.' '0'..'9'+ 'E' ('+' | '-')? '0'..'9'+);
INT: '0'..'9'+ ;
WS: ( ' ' | '\t' | '\r' | '\n')+ {$channel=HIDDEN;} ;