aslike 0.1.1

ASLIKE

struct Like(T) if (is(T == interface)) -- wrap structure for T, it have methods and private delegate fields matches all methods from T.

Like!T as(T, X)(auto ref X obj) if (is(T == interface)) -- wrapper method, wrap object X obj into Like!T if it possible (fill all delegate fields in returned Like!T with methods pointers from obj).

It can be helpful if you want to declare function or method what must get some object as argument, and it object must contains all methods what you want, and if you don't want use OOP and/or want use structs.

You can use templates for this, but you can't override class methods at this case, and templace can be less readable what using interface type.

struct wrap example

Or if you want cache virtual methods table lookup for improving performance.

cache wrap example

Using

1. define interface

   interface Foo
   {
       void func1();
       int func2(int a, int b);
   }
   

2. use Like!Foo as argument type

   int bar(Like!Foo obj, int a, int b)
   {
       obj.func1();
       return obj.func2(a, b);
   }
   

3. wrap object by as function

   struct SFoo
   {
       int field;
       void func1() { field++; }
       int func2(int a, int b) { return a + b / field; }
   }
   

   auto x = SFoo(10);
   writeln(bar(x.as!Foo));
   

Notes

Like struct have reference symantics respect to wrapped object.