Welcome to the CHICKEN Scheme pasting service

(let ((keys (option-keys))                       (vals ((request-vars))))                   (map (lambda (key)                          (let ((l (filter-map (lambda (val)                                                 (and (eqv? (car val) key)                                                      (cdr val)))                                               vals)))                            (list key (if (> (length l) 1)                                          (chop l 2)                                          (car l)))))                        keys))