I have a generic List-like class tMyList<B>
with a method Each() which iterated over each element and calls anonymous procedure tMyList<A>.enumProc
with paramenter - the current item of type <B>
.
I want to implement the class as an Interface for easier lifetime management.
The problem is I cannot declare the Each method in the iMyList<A>
interface, because tMyList<A>.enumProc
type is unknown. As far as I know Interfaces does not support nested types?
Here is the code:
tMyList<B> = class;
iMyList<A> = interface
procedure each(enumProcedure: iMyList<A>.enumProc); // ERROR - Undeclared identifier: 'enumProc'
end;
tMyList<B> = class(tInterfacedObject, iMyList<B>)
type
enumProc = reference to procedure(item: iMyList<B>);
public
procedure each(enumProcedure: enumProc);
end;
*
Implementing Enumerator is not an option in this particular case
The only way that you can make this work is to define the procedural type outside of the implementing class. Like this: