On Monday, 28 May 2018 at 09:59:50 UTC, DigitalDesigns wrote:
Implementing interfaces can be a pain but are necessary.
I like to use abstract classes and provide a base
implementation. It would be cool if I could use D's awesome
meta features to extract the interface from the abstract class
then build it. This requires some funky stuff which I'm not
sure D can do
Creating an interface based on a class is no big deal in D:
interface Interface(T)
{
import std.traits;
static foreach (fn; __traits(allMembers, T))
static foreach (overload; MemberFunctionsTuple!(T, fn))
mixin("ReturnType!overload
"~fn~"(Parameters!overload);");
}
class A
{
void fun() {}
}
alias IA = Interface!A;
However, you run into a problem when A is expected to implement
IA: in order to figure out which functions should be in the
interface, we need to know which functions are in A. And in order
to figure out which functions are in A, we need to know which
functions are in IA. It's a loop with no real solution.
In this specific case, one could consider only members of A,
ignoring any interfaces or base classes. This isn't currently
possible, but it's not an entirely unreasonable enhancement
request.
--
Simen
