X-Git-Url: https://git.hcoop.net/clinton/lisp-on-lines.git/blobdiff_plain/e7c5f95a989882cabc1f4b6ea4598565ea317952..f56d6e7e926f9c3f968325e244794ff748435ac3:/src/display.lisp

diff --git a/src/display.lisp b/src/display.lisp
index 91cbd06..6078e83 100644
--- a/src/display.lisp
+++ b/src/display.lisp
@@ -1,44 +1,80 @@
 (in-package :lisp-on-lines)
 
-(defvar *object*)
+
 (defvar *display*)
 
+
 (define-layered-function display-using-description (description display object &rest args)
   (:documentation
    "Displays OBJECT via description using/in/with/on display"))
 
-(defun display (display object &rest args)
-  (display-using-description (description-of object) display object args))
+
+
+(defun modify-layer-context (context &key activate deactivate)
+  (dolist (d deactivate)
+    (setf context (remove-layer (find-description d)
+				context)))
+  (dolist (d activate context)
+    (setf context (adjoin-layer (find-description d)
+				context))))
+
+(defun funcall-with-attribute-context (attribute thunk)
+  (funcall-with-layer-context 
+   (modify-layer-context (current-layer-context) 
+			 :activate (attribute-active-descriptions attribute)
+			 :deactivate (attribute-inactive-descriptions attribute))
+   thunk))
+
+(defmacro with-attribute-context ((attribute) &body body)
+  `(funcall-with-attribute-context ,attribute (lambda () ,@body)))
+  
+  
+(defun display (display object &rest args &key deactivate activate &allow-other-keys)
+
+  (funcall-with-layer-context 
+   (modify-layer-context (current-layer-context) 
+			 :activate activate 
+			 :deactivate deactivate)
+   (lambda () 
+     (apply #'display-using-description (description-of object) display object args))))
 
 (define-layered-method display-using-description 
   :around (description display object &rest args)
-  (let ((*display* display)
-	(*object*  object))
-    (call-next-method)))
+  (declare (ignorable args))
+#+nil  (break "Entering DISPLAY for ~A on ~A using ~A" object display description)
+  (let ((*display* display))
+    (apply #'funcall-with-described-object 
+     (lambda ()
+       (call-next-method))
+     object description args)))
+
+
+
+(defun display/d (&rest args)
+  (apply #'display-using-description args))
 
 (define-layered-method display-using-description (description display object &rest args)
  (error "No DISPLAY-USING-DESCRIPTION methods are specified for: ~%  DESCRIPTION: ~A ~%  DISPLAY: ~A ~%  OBJECT: ~A ~%  ARGS: ~S
 
 OMGWTF! If you didn't do this, it's a bug!" description display object args))
 
-(defun display-attribute (attribute)
-  (display-using-description attribute *display* *object*))
-
 (defmacro define-display (&body body)
-  (loop with in-layerp = (eq (car body) :in-layer)
-	with layer = (if in-layerp (cadr body) 't)
-	for tail on (if in-layerp (cddr body) body)
+  (loop with in-descriptionp = (eq (car body) :in-description)
+	with description = (if in-descriptionp (cadr body) 't)
+	for tail on (if in-descriptionp (cddr body) body)
 	until (listp (car tail))
 	collect (car tail) into qualifiers
 	finally
-	(when (member :in-layer qualifiers)
-	  (error "Incorrect occurrence of :in-layer in defdisplay. Must occur before qualifiers."))
+	(when (member :in-description qualifiers)
+	  (error "Incorrect occurrence of :in-description in defdisplay. Must occur before qualifiers."))
 	(return
 	  (destructuring-bind (description-spec &optional  (display-spec (gensym)) (object-spec (gensym))) 
 	      (car tail) 
-		`(define-layered-method
+	    `(define-layered-method
 		  display-using-description
-		   :in-layer ,layer
+		   :in-layer ,(if (eq t description) 
+				  t
+				  (defining-description description))
 		   ,@qualifiers
 		   (,(if (listp description-spec)
 		        (list (first description-spec)