Core.logic equivalent of multimethods

Question

I need to define predicates to which I can later (and from other namespaces) attach further clauses (so not just facts). I couldn't find any such functionality in the source. Due to the extensive use of macros, hacking such a system onto core.logic from the outside is extremely difficult, if not impossible (to me at least).

I'd love to implement this myself too, if given an OK and rough direction.

Answer 1

Comment made by: werg

I actually did manage to tack on a prototype that covers the basic behavior I would like to see: (link: https://github.com/werg/herpderp/blob/master/src/herpderp/multo.clj)

I use a set stored in a ref in the defne's metadata to manage dynamic changes to the clauses. Upon changing that set using defclause I use eval to re-define the var using defne.

This might not be nice, but allows me to continue developing features against it.

Answer 2

Comment made by: dnolen

I don't think the current implementation can really support this and I don't think it's wise to try to hack around the current implementation. I'd be willing to consider a comprehensive solution if someone is willing to do the legwork.

Answer 3

Reference: https://clojure.atlassian.net/browse/LOGIC-35 (reported by alex+import)