The design of the Clojure code can be clearly seen from the Python code. But I'm not sure if that's idiomatic Clojure. I'd like to see what the Clojure version would look like if a Clojure programmer solved the problem without looking at the Python code first. That would give me more insight into the differences between the languages.
Follow Norvig's lead from Paradigms of Artificial Inteligence - write fast embedded paradigms. So write a performant Constraint Solver DSL couple it with a performant Prolog DSL. Solve all kinds of problems declaratively instead of just Sudoku. I've been working on that https://github.com/swannodette/logos ;)
Yeah, I started a port of this code into Clojure about a year ago with no attempt to keep the design and it diverged a bit. I never finished it though as my plane landed. :)
