downs Wrote:
> Craig Kuhnert wrote:
> > Hi
> > I am trying to convert some code I wrote in C++ to D to give it a try and I
> > have come across some code that I dont know how to convert.
> > I have simplified the code to illustrate the problem I have.
> > How do I do this in D?
> >
> > class IFieldSetter
> > {
> > public:
> > virtual void SetValue(void * object, const void * value) = 0;
> > };
> >
> > template <class C, class T>
> > class FieldSetter : public IFieldSetter
> > {
> > private:
> > typedef T (C::* MemberField);
> > MemberField field;
> >
> > public:
> > FieldSetter(MemberField afield)
> > : field(afield)
> > {}
> >
> > void SetTypedValue(C * object, const T& value)
> > {
> > object->*field = value;
> > }
> >
> > void SetValue(void * object, const void * value)
> > {
> > SetTypedValue((C*) object, (const T&) value);
> > }
> > };
> >
> > class MySampleClass
> > {
> > public:
> > int Status;
> > std::string Name;
> > };
> >
> > void main(void)
> > {
> > IFieldSetter * StatusSetter = new
> > FieldSetter<MySampleClass,int>(&MySampleClass::Status);
> > IFieldSetter * NameSetter = new
> > FieldSetter<MySampleClass,std::string>(&MySampleClass::Name);
> >
> > MySampleClass * a = new MySampleClass();
> > MySampleClass * b = new MySampleClass();
> >
> > StatusSetter->SetValue(a, (void*)20);
> > StatusSetter->SetValue(b, (void*)40);
> >
> > NameSetter->SetValue(a, "2002");
> > NameSetter->SetValue(b, "2002");
> > }
> >
> > Thanks
> > Craig
>
> If I'm getting this correctly, here's one way to do it ..
>
> module test;
>
> import std.stdio, tools.ctfe: ctReplace; // easy to write your own ctReplace
> function
>
> template Init(T) { T Init; }
>
> interface IFieldSetter {
> void setValue(Object obj, void* value);
> }
>
> class FieldSetter(T: Object, string Name) : IFieldSetter {
> override void setValue(Object obj, void* value) {
> auto tee = cast(T) obj;
> mixin("tee.%NAME = *cast(typeof(tee.%NAME)*) value; ".ctReplace("%NAME",
> Name));
> }
> void setValue(T obj, typeof(mixin("Init!(T)."~Name)) value) {
> mixin("obj.%NAME = value; ".ctReplace("%NAME", Name));
> }
> }
>
> class Sample {
> int status;
> string name;
> }
>
> void main() {
> auto statSetter = new FieldSetter!(Sample, "status");
> auto nameSetter = new FieldSetter!(Sample, "name");
> auto sample = new Sample;
> int i = 20;
> statSetter.setValue(sample, &i);
> statSetter.setValue(sample, 40);
> nameSetter.setValue(sample, "Fooblr");
> }
Thanks
Thats brilliant! D rocks!
I never though of using mixin for that purpose.
