public override object VisitExprSign([NotNull] MiniSQLParser.ExprSignContext context)
{
Expression left = (Expression)Visit(context.expr());
// optimize expression
if (context.PLUS_OPERATOR() != null)
{
if (left.ConcreteValue.Type == AttributeTypes.Char)
{
throw new System.InvalidOperationException("Operator '+' cannot be applied to operand of type 'string'");
}
return(left);
}
// if (left.Operator == Operator.AtomConcreteValue)
// {
// if (left.ConcreteValue.Type == AttributeType.Char)
// throw new System.InvalidOperationException("Operator '-' cannot be applied to operand of type 'string'");
// if (left.ConcreteValue.Type == AttributeType.Int)
// left.ConcreteValue.IntegerValue = -left.ConcreteValue.IntegerValue;
// if (left.ConcreteValue.Type == AttributeType.Float)
// left.ConcreteValue.FloatValue = -left.ConcreteValue.FloatValue;
// return left;
// }
Expression obj = new Expression();
obj.LeftOperand = left;
obj.Operator = Operator.Negative;
// optimize expression
if (left.Operator == Operator.AtomConcreteValue)
{
left.ConcreteValue = obj.Calculate(null);
return(left);
}
return(obj);
}
