Functional is one of the many possible idioms of declarative programming.
It's just one that's completely focused on an idealization of "software", instead of any more concrete problem. That makes it more general than most. And the functional idealization is more similar to what real computers run than other representations (some people already mentioned Prolog). Those give FP some advantages over the others, at least for now.
It's just one that's completely focused on an idealization of "software", instead of any more concrete problem. That makes it more general than most. And the functional idealization is more similar to what real computers run than other representations (some people already mentioned Prolog). Those give FP some advantages over the others, at least for now.