clisp の sys::hash-table-iterator などを #xyzzy Lisp に移植

gistfile1.lisp

(defun package-iterator (package-list &rest symbol-type)
  (when (endp symbol-type)
    (error "symbol-typeが指定されていません"))
  (when (atom package-list)
    (setf package-list (list package-list)))
  (let (current-symbols)
    #'(lambda ()
        (when (or current-symbols
                  symbol-type)
          (unless current-symbols
            (macrolet ((push-all ()
                         (loop
                           (multiple-value-bind (f symbol type package)
                               (next)
                             (unless f
                               (return))
                             (push (list f symbol type) current-symbols)))))
              (case (car symbol-type)
                (:external
                 (with-package-iterator (next package-list :external)
                   (push-all)))
                (:internal
                 (with-package-iterator (next package-list :internal)
                   (push-all)))
                (:inherited
                 (with-package-iterator (next (mapcan #'package-use-list package-list) :external)
                   (push-all)))
                (t (error "未定義のシンボルタイプです: ~S" (car symbol-type))))
              (setf symbol-type (cdr symbol-type)
                    current-symbols (nreverse current-symbols))
              ))
          (values-list (pop current-symbols))))))

(defun package-iterate (iterator)
  (funcall iterator))

(defun hash-table-iterator (hash-table)
  (let ((i 0))
    #'(lambda ()
        (multiple-value-setq (i key val)
          (si:*enum-hash-table hash-table i))
        (if i (values t key val)))))

(defun hash-table-iterate (iterator)
  (funcall iterator))