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 (defun funcall-with-attribute-context (attribute thunk)
  22   (funcall-with-layer-context
  23    (modify-layer-context (current-layer-context)
  24                          :activate (attribute-active-descriptions attribute)
  25                          :deactivate (attribute-inactive-descriptions attribute))
  26    thunk))
  27
  28 (defmacro with-attribute-context ((attribute) &body body)
  29   `(funcall-with-attribute-context ,attribute (lambda () ,@body)))
  30
  31
  32 (defun display (display object &rest args &key deactivate activate &allow-other-keys)
  33
  34   (funcall-with-layer-context
  35    (modify-layer-context (current-layer-context)
  36                          :activate activate
  37                          :deactivate deactivate)
  38    (lambda ()
  39      (apply #'display-using-description (description-of object) display object args))))
  40
  41 (define-layered-method display-using-description
  42   :around (description display object &rest args)
  43   (declare (ignorable args))
  44 #+nil  (break "Entering DISPLAY for ~A on ~A using ~A" object display description)
  45   (let ((*display* display))
  46     (apply #'funcall-with-described-object
  47      (lambda ()
  48        (call-next-method))
  49      object description args)))
  50
  51
  52
  53 (defun display/d (&rest args)
  54   (apply #'display-using-description args))
  55
  56 (define-layered-method display-using-description (description display object &rest args)
  57  (error "No DISPLAY-USING-DESCRIPTION methods are specified for: ~%  DESCRIPTION: ~A ~%  DISPLAY: ~A ~%  OBJECT: ~A ~%  ARGS: ~S
  58
  59 OMGWTF! If you didn't do this, it's a bug!" description display object args))
  60
  61 (defmacro define-display (&body body)
  62   (loop with in-descriptionp = (eq (car body) :in-description)
  63         with description = (if in-descriptionp (cadr body) 't)
  64         for tail on (if in-descriptionp (cddr body) body)
  65         until (listp (car tail))
  66         collect (car tail) into qualifiers
  67         finally
  68         (when (member :in-description qualifiers)
  69           (error "Incorrect occurrence of :in-description in defdisplay. Must occur before qualifiers."))
  70         (return
  71           (destructuring-bind (description-spec &optional  (display-spec (gensym)) (object-spec (gensym)))
  72               (car tail)
  73             `(define-layered-method
  74                   display-using-description
  75                    :in-layer ,(if (eq t description)
  76                                   t
  77                                   (defining-description description))
  78                    ,@qualifiers
  79                    (,(if (listp description-spec)
  80                         (list (first description-spec)
  81                              (if (eq 'description (second description-spec))
  82                                      'description
  83                                      (defining-description (second description-spec)))))
  84                    ,display-spec
  85                    ,object-spec &rest args)
  86                    (declare (ignorable args))
  87                    ,@(cdr tail))))))
  88
  89
  90
  91