I've seen some poorly implemented rules engines in my day. I've often thought there must be a programming language out there build specifically for rules and wo

I've seen some poorly implemented rules engines in my day. I've often thought there must be a programming language out there build specifically for rules and workflows, like how Erlang is designed for concurrency. I know there is the Windows Workflow Foundation, but I want something which doesn't necessarily have to be compiled, but that I can translate user input directly into a new rule set.