case

(case key (k1 body...) ((k2 k3) body...) (otherwise body...))

Evaluates key once and compares it with eql against each clause's unevaluated key(s), running the body of the first match and returning its last value. A clause whose key is a list matches if key is eql to any element of that list. A final t or otherwise clause is the default; if nothing matches and there is no default, case returns nil.