src/display.lisp

   1 (in-package :lisp-on-lines)
   2
   3
   4 (defvar *display*)
   5
   6
   7 (define-layered-function display-using-description (description display object &rest args)
   8   (:documentation
   9    "Displays OBJECT via description using/in/with/on display"))
  10
  11
  12
  13 (defun modify-layer-context (context &key activate deactivate)
  14   (dolist (d deactivate)
  15     (setf context (remove-layer (find-description d)
  16                                 context)))
  17   (dolist (d activate context)
  18     (setf context (adjoin-layer (find-description d)
  19                                 context))))
  20
  21
  22
  23
  24 (defun display (display object &rest args &key deactivate activate &allow-other-keys)
  25
  26   (funcall-with-layer-context
  27    (modify-layer-context (current-layer-context)
  28                          :activate activate
  29                          :deactivate deactivate)
  30    (lambda ()
  31      (apply #'display-using-description (description-of object) display object args))))
  32
  33 (define-layered-method display-using-description
  34   :around (description display object &rest args)
  35   (declare (ignorable args))
  36 #+nil  (break "Entering DISPLAY for ~A on ~A using ~A" object display description)
  37   (let ((*display* display))
  38     (apply #'funcall-with-described-object
  39      (lambda ()
  40        (call-next-method))
  41      object description args)))
  42
  43
  44
  45
  46
  47 (defun display/d (&rest args)
  48   (apply #'display-using-description args))
  49
  50 (define-layered-method display-using-description (description display object &rest args)
  51  (error "No DISPLAY-USING-DESCRIPTION methods are specified for: ~%  DESCRIPTION: ~A ~%  DISPLAY: ~A ~%  OBJECT: ~A ~%  ARGS: ~S
  52
  53 OMGWTF! If you didn't do this, it's a bug!" description display object args))
  54
  55 (defmacro define-display (&body body)
  56   (loop with in-descriptionp = (eq (car body) :in-description)
  57         with description = (if in-descriptionp (cadr body) 't)
  58         for tail on (if in-descriptionp (cddr body) body)
  59         until (listp (car tail))
  60         collect (car tail) into qualifiers
  61         finally
  62         (when (member :in-description qualifiers)
  63           (error "Incorrect occurrence of :in-description in defdisplay. Must occur before qualifiers."))
  64         (return
  65           (destructuring-bind (description-spec &optional  (display-spec (gensym)) (object-spec (gensym)))
  66               (car tail)
  67             `(define-layered-method
  68                   display-using-description
  69                    :in-layer ,(if (eq t description)
  70                                   t
  71                                   (defining-description description))
  72                    ,@qualifiers
  73                    (,(if (listp description-spec)
  74                         (list (first description-spec)
  75                              (if (eq 'description (second description-spec))
  76                                      'description
  77                                      (defining-description (second description-spec)))))
  78                    ,display-spec
  79                    ,object-spec &rest args)
  80                    (declare (ignorable args))
  81                    ,@(cdr tail))))))
  82
  83
  84
  85