I keep meaning to learn Prolog, but I've had trouble finding anything that I'm doing that is a good fit for it. I suspect most of that is sapir-whorf-thing on my end; I'm so used to the current tooling that it's influencing how I think about the problem space and so a pattern I'm not super familiar with doesn't enter into my brain.<p>That said, I never really thought of Erlang as a logic language, so I'm not sure exactly what this reference sheet is actually for?
Would be interesting to see how much more involved it is to solve a constraint programming or optimization problem (something you'd actually use prolog for) in the other languages.