code: function parseMultiplicativeExpression() {
          var expr = parseUnaryExpression();
  
          while (match('*') || match('/') || match('%')) {
              expr = {
                  type: Syntax.BinaryExpression,
                  operator: lex().value,
                  left: expr,
                  right: parseUnaryExpression()
              };
          }
  
          return expr;
      }
docs: 11.5 Multiplicative Operators