unific

https://github.com/jimwise/unific

Unific is a ruby unification engine. A unification engine is an essential part of a logic programming environment (the whole logic programming environment this is taken from is available as the in-development Rulog[http://github.com/jimwise/rulog] (Ruby With Logic) gem), but can also be useful on its own as a pattern matching engine which can enforce consistency across multiple matches.