Expression.g4

grammar Expression;

@header {
package sample;
}

expression: expression PLUS expression # Addition
            |   expression TIMES expression # Multiplication
            |   INT # Integer
            |   OPENING_PARENTHESIS expression CLOSING_PARENTHESIS # InParenthesesExpression ;

OPENING_PARENTHESIS: '(';
CLOSING_PARENTHESIS: ')';
PLUS : '+';
TIMES : '*';
INT : [0-9]+ ;