Let me sing half a praise: I learned Prolog at university through three courses and learned to love it for a certain set of problems. Everything with multiple o

Let me sing half a praise: I learned Prolog at university through three courses and learned to love it for a certain set of problems. Everything with multiple outcomes or things that map well to descriptions trough constraints are very easy in prolog. Conceptually, it is well removed from other languages and therefore worthwhile learning. Prolog naturally teaches you interesting approaches to work with data. Writing parts of my software in Prolog is still an option for me. Practically, though, it suffers from real world problems: there are quite a few of runtime systems, dropping in and out of maintenance every once in a while. Lots of things are semi-standard, for example each runtime ships with a constraint library with different behavior. (e.g. in one Prolog, applying a constraint to a variable that already has a value is an error, in others, it is allowed if the variable satisfies the constraint). Prolog is really more a family of languages, sharing a similar syntax.