;;;
;;; gauche/mop/validator.scm - validator slot option
;;;
;;;   Copyright (c) 2000-2020  Shiro Kawai  <shiro@acm.org>
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(define-module gauche.mop.validator
  (export <validator-meta> <validator-mixin>)
  )
(select-module gauche.mop.validator)

(define-class <validator-meta> (<class>)
  ())

(define-method compute-get-n-set ((class <validator-meta>) slot)
  (let ([pre  (slot-definition-option slot :validator #f)]
        [post (slot-definition-option slot :observer #f)])
    (if (or pre post)
      (let* ([acc (compute-slot-accessor class slot (next-method))]
             [getter (^o (slot-ref-using-accessor o acc))]
             [bound? (^o (slot-bound-using-accessor? o acc))]
             [setter (cond [(and pre post)
                            (^[o v]
                              (slot-set-using-accessor! o acc (pre o v))
                              (post o (slot-ref-using-accessor o acc)))]
                           [pre
                            (^[o v]
                              (slot-set-using-accessor! o acc (pre o v)))]
                           [else
                            (^[o v]
                              (slot-set-using-accessor! o acc v)
                              (post o (slot-ref-using-accessor o acc)))])])
        ;; the last #t enables initialization by :initform etc.
        (list getter setter bound? #t))
      (next-method))))

;; convenience base class.  you can either inherit <validator-mixin>,
;; or specifying :metaclass <validator-meta> to your class.
(define-class <validator-mixin> ()
  ()
  :metaclass <validator-meta>)

