screamer

i'm a long time lisper, but i don't think this is justified. implementing prolog/backtracking on top of lisp is certainly possible and not even too hard (see e.g. https://github.com/nikodemus/screamer) and implementing Coq on top of lisp is also possible. but IMO the "with ease" phrase is not justified in this context. if you only mean that lisp will not be in the way if you set out to implement these, then i agree. lisp -- the language and the typical opensource implementation -- will be much less of an obstacle than other languages when chosen as foundations.

The most beautiful I'm aware of is Robert Strandh's SICL (https://github.com/robert-strandh/SICL). CL-PPCRE (https://github.com/edicl/cl-ppcre) is very nice as well, imo. What makes them beautiful? They're very straight forward and clearly communicate what they're doing, and how. And the parentheses in their language of choice softens the visual display of the code -- while the semantics of the language cause the shape of the code to communicate quite a bit about how the machine will go about executing it. There are no surprises. In terms of conceptual beauty, it'd be hard to beat Screamer (https://github.com/nikodemus/screamer). What makes this beautiful? The way it makes a hairy problem seem simple and straight-forward.

Probabilistic programming in Common Lisp: https://github.com/nikodemus/screamer

Genworks doesn't come with a constraint solver, but you can use the Screamer constraint solving library with it: http://weitz.de/eclm2008/Selvaag%20Bluethink%20House%20Desig... https://www.youtube.com/watch?v=usoKR80tWzw https://github.com/nikodemus/screamer