Sorry, I'm not a web programmer. I am a compiler developer, and I have used Prolog with great success in compiler code: Unification is great for matching patter

Sorry, I'm not a web programmer. I am a compiler developer, and I have used Prolog with great success in compiler code: Unification is great for matching patterns in tree-shaped structures like abstract syntax trees representing programs. It should be the same for the abstract syntax trees representing web pages. I understand if this is too hypothetical for you. The other point still stands, that Prolog's native data model allows you to represent tree-shaped (and DAG-shaped) documents just as naturally as Ruby, Lua, etc.