I see search as a particular kind of problem that would be defined in a library, not a language. Unless it's a language built specifically to solve constraints

I see search as a particular kind of problem that would be defined in a library, not a language. Unless it's a language built specifically to solve constraints (i.e., a logic programming language), which Erlang is not. Can you point out where within Erlang you feel backtracking should be supported by the core library? It sounds to me like you want the language to be something it fundamentally isn't; i.e., more Prolog-like, and I'm uncertain as to why.