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 (if (consp d) (car d) 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    (lambda ()
  27      (with-special-symbol-access
  28        (contextl::funcall-with-special-initargs
  29         (without-special-symbol-access
  30           (mappend (lambda (desc)
  31                      (when (consp desc)
  32                        (let ((description (find-description (car desc))))
  33                          (loop
  34                             :for (key val) :on (cdr desc) :by #'cddr
  35                             :collect (list (find key (description-attributes description)
  36                                                  :key #'attribute-keyword)
  37                                            :value val)))))
  38                    (attribute-active-descriptions attribute)))
  39         (lambda ()
  40           (without-special-symbol-access
  41             (funcall thunk))))))))
  42
  43 (defmacro with-attribute-context ((attribute) &body body)
  44   `(funcall-with-attribute-context ,attribute (lambda () ,@body)))
  45
  46
  47 (defun display (display object &rest args &key deactivate activate &allow-other-keys)
  48   (funcall-with-layer-context
  49    (modify-layer-context (current-layer-context)
  50                          :activate activate
  51                          :deactivate deactivate)
  52    (lambda ()
  53      (apply #'display-using-description (description-of object) display object args))))
  54
  55 (define-layered-method display-using-description
  56   :around ((description standard-description-object) display object &rest args)
  57   (declare (ignorable args))
  58 #+nil  (break "Entering DISPLAY for ~A on ~A using ~A" object display description)
  59   (let ((*display* display))
  60     (apply #'funcall-with-described-object
  61      (lambda ()
  62        (call-next-method))
  63      object description args)))
  64
  65
  66
  67
  68 (defun display/d (&rest args)
  69   (apply #'display-using-description args))
  70
  71 (define-layered-method display-using-description (description display object &rest args)
  72  (error "No DISPLAY-USING-DESCRIPTION methods are specified for: ~%  DESCRIPTION: ~A ~%  DISPLAY: ~A ~%  OBJECT: ~A ~%  ARGS: ~S
  73
  74 OMGWTF! If you didn't do this, it's a bug!" description display object args))
  75
  76 (defmacro define-display (&body body)
  77   (loop with in-descriptionp = (eq (car body) :in-description)
  78         with description = (if in-descriptionp (cadr body) 't)
  79         for tail on (if in-descriptionp (cddr body) body)
  80         until (listp (car tail))
  81         collect (car tail) into qualifiers
  82         finally
  83         (when (member :in-description qualifiers)
  84           (error "Incorrect occurrence of :in-description in defdisplay. Must occur before qualifiers."))
  85         (return
  86           (destructuring-bind (description-spec &optional  (display-spec (gensym)) (object-spec (gensym)))
  87               (car tail)
  88             `(define-layered-method
  89                   display-using-description
  90                    :in-layer ,(if (eq t description)
  91                                   t
  92                                   (defining-description description))
  93                    ,@qualifiers
  94                    (,(if (listp description-spec)
  95                         (list (first description-spec)
  96                              (if (eq 'description (second description-spec))
  97                                      'description
  98                                      (contextl::defining-layer (defining-description (second description-spec))))))
  99                    ,display-spec
 100                    ,object-spec &rest args)
 101                    (declare (ignorable args))
 102                    ,@(cdr tail))))))
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