(in-package hemlock)

;;; Scratch windows' documents have their ns:isa slots reset
(defclass ns::my-ns-document (ns:ns-document)
         ()
         (:metaclass ns:+ns-object))
(declaim (special ns::my-ns-document))

(defun cl-user::my (&optional (scratch-p t))
  (gui::execute-in-gui
   (lambda nil
     (let* ((hview (gui::find-or-make-hemlock-view nil))
            (buffer (hemlock-view-buffer hview))
            (window (#/window (hi::hemlock-view-pane hview)))
            (wc (#/windowController window))
            (document (#/document wc))
            (stream (hi:make-hemlock-output-stream (buffer-end-mark buffer) :none)))
       ; All possible values {:none, :line, :full} have identical effect)
       (#/setTitle: window (objc::make-nsstring (copy-seq "My title")))
       (when scratch-p
         (setf (slot-value document 'ns:isa) (find-class 'ns::my-ns-document)))
       (format stream "A change~%")))))