lispdoc - results for while-collecting

(asdf:while-collecting (&rest collectors) &body body)
Function: COLLECTORS should be a list of names for collections. A collector defines a function that, when applied to an argument inside BODY, will add its argument to the corresponding collection. Returns multiple values, a list for each collection, in order. E.g., (while-collecting (foo bar) (dolist (x '((a 1) (b 2) (c 3))) (foo (first x)) (bar (second x)))) Returns two values: (A B C) and (1 2 3).