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digitalmars.D.learn - Templated Inheritance

reply Jesse Phillips <jessekphillips gmail.com> writes:
Templates, traits, mixins, and meta programming I haven't really gotten 
into. But I came to note that templating inheritance of a class works 
great.

http://dsource.org/projects/tutorials/wiki/TemplatedInheritanceExample

My question is what others think about the possibility of using traits 
from D2.0 to allow for interface instantiation without reimplementing 
methods? I don't know how practical it would be but it might be quite 
interesting.
Mar 02 2008
parent Christopher Wright <dhasenan gmail.com> writes:
Jesse Phillips wrote:
 Templates, traits, mixins, and meta programming I haven't really gotten 
 into. But I came to note that templating inheritance of a class works 
 great.
 
 http://dsource.org/projects/tutorials/wiki/TemplatedInheritanceExample
 
 My question is what others think about the possibility of using traits 
 from D2.0 to allow for interface instantiation without reimplementing 
 methods? I don't know how practical it would be but it might be quite 
 interesting.

I have an example, and a usable one, that basically proxies a class or interface using templated inheritance. It doesn't quite support concrete classes right now, because I want a reliable solution, and a concrete class could define a constructor that throws an exception or dereferences a null pointer or some such. All the virtual methods for the concrete class will be properly proxied; it's just that you depend on the constructor to work correctly. The code's here: http://www.dsource.org/projects/dmocks/browser/trunk/dmocks/dmocks/MethodMock.d http://www.dsource.org/projects/dmocks/browser/trunk/dmocks/dmocks/MockObject.d Not really that difficult. How it applies to your question isn't quite clear, though; you want your interface methods to do something useful. The typical tactic with that is to define a mixin with default implementations. Works best if you do that with an abstract base class and then override whatever you need to, I think.
Mar 02 2008