Prolog was inspiration for the Erlang syntax and it's about as declarative as you can get. In Prolog, everything is either a fact or a rule involving facts. If

Prolog was inspiration for the Erlang syntax and it's about as declarative as you can get. In Prolog, everything is either a fact or a rule involving facts. If you leave some variables unbound, you get what we think of as a program, where the system tries to infer values.