cond

(cond (test body...)...)

Evaluates each clause's test in order and, for the first one that is truthy (non-nil), evaluates that clause's body forms and returns the value of the last. A clause with no body returns the value of its own test. If no test is truthy cond returns nil; a final (t body...) clause acts as a catch-all default. It expands into nested if forms.