public override object VisitConcat(BoundConcatEx x)
{
return(x.Update(VisitImmutableArray(x.ArgumentsInSourceOrder)));
}
public override object VisitConcat(BoundConcatEx x)
{
// transform arguments first:
x = (BoundConcatEx)base.VisitConcat(x);
//
var args = x.ArgumentsInSourceOrder;
if (args.Length == 0 || args.All(IsEmptyString))
{
// empty string:
TransformationCount++;
return(new BoundLiteral(string.Empty)
{
ConstantValue = new Optional <object>(string.Empty)
}.WithContext(x));
}
// visit & concat in compile time if we can:
var newargs = args;
int i = 0;
do
{
// accumulate evaluated string value if possible:
if (newargs[i].Value.ConstantValue.TryConvertToString(out var value))
{
string result = value;
int end = i + 1;
while (end < newargs.Length && newargs[end].Value.ConstantValue.TryConvertToString(out var tmp))
{
result += tmp;
end++;
}
if (end > i + 1) // we concat'ed something!
{
newargs = newargs.RemoveRange(i, end - i);
if (!string.IsNullOrEmpty(result))
{
newargs = newargs.Insert(i, BoundArgument.Create(new BoundLiteral(result)
{
ConstantValue = new Optional <object>(result),
TypeRefMask = _routine.TypeRefContext.GetStringTypeMask(),
ResultType = DeclaringCompilation.CoreTypes.String,
}.WithAccess(BoundAccess.Read)));
}
}
}
//
i++;
} while (i < newargs.Length);
//
if (newargs != args)
{
TransformationCount++;
if (newargs.Length == 0)
{
return(new BoundLiteral(string.Empty)
{
ConstantValue = new Optional <object>(string.Empty)
}.WithContext(x));
}
else if (newargs.Length == 1 && newargs[0].Value.ConstantValue.TryConvertToString(out var value))
{
// "value"
return(new BoundLiteral(value)
{
ConstantValue = new Optional <object>(value)
}.WithContext(x));
}
//
return(x.Update(newargs));
}
//
return(x);
}