code: @Override
      public Object visitExponentExpression(ExcellentParser.ExponentExpressionContext ctx) {
          BigDecimal arg1 = Conversions.toDecimal(visit(ctx.expression(0)), m_evalContext);
          BigDecimal arg2 = Conversions.toDecimal(visit(ctx.expression(1)), m_evalContext);
          return ExpressionUtils.decimalPow(arg1, arg2);
      }
docs: expression: expression EXPONENT expression