keyword-procs2.scm

(use srfi-1)
(use gauche.test)


;; return values of pair keywords and single keywords.
(define (pairs&singles lis)
  (define (loop lis pairs singles)
    (if (null? (cdr lis))
      (if (and (pair? lis) (keyword? (car lis)))
        (values (filter (lambda (elt) (not (eq? (car lis) elt)))
                        pairs)
                (cons (car lis) singles))
        (values pairs singles))
      (cond
        [(and (keyword? (car lis))
           ((complement keyword?) (cadr lis)))    ; pair (:key val ...)
         (loop (cddr lis)
               pairs
               singles)]
        [(and (keyword? (car lis))
           (keyword? (cadr lis)))    ; single (:key :key ...)
         (loop (cdr lis)
               (filter (lambda (elt) (not (eq? (car lis) elt)))
                       pairs)
               (cons (car lis) singles))]
        [else (error "not keyword list" lis)])
      ))
  (loop lis lis '()))

(define (ctrl/keyword . args)
  (receive (args singles) (pairs&singles args)
    (let-keywords args [(value #f)
                        ; (proc (lambda (elt) elt))
                        ]
      (when (find (cut eq :show <>) singles)
        (print value))
      )))


(define (main args)
  (ctrl/keyword :show)
  (ctrl/keyword :value "hoge" :show)

  0)