X-Git-Url: https://git.hcoop.net/clinton/lisp-on-lines.git/blobdiff_plain/4271ab0badc43ec1c9ac5a9f71b8995702802234..2548f0540da69973512f1827b2bfd2360470bb27:/src/description.lisp

diff --git a/src/description.lisp b/src/description.lisp
index c06a6f4..d373ace 100644
--- a/src/description.lisp
+++ b/src/description.lisp
@@ -1,5 +1,8 @@
 (in-package :lisp-on-lines)
 
+(defvar *object* nil)
+(defvar *description*)
+
 (define-layered-function description-of (thing)
   (:method (thing)
     (find-description 't)))
@@ -7,35 +10,105 @@
 (defun description-print-name (description)
   (description-class-name (class-of description)))
 
-(defun find-attribute (description attribute-name)
-  (slot-value description attribute-name))
-
-
 (defun description-attributes (description)
-  (mapcar (curry
-	   #'slot-value-using-class 
-	   (class-of 'description)
-	   description) 
-	  (class-slots (class-of description))))
-
-(defvar *display-attributes* nil)
-(defun attribute-active-p (attribute)
-  (or (null *display-attributes*)
-      (find (attribute-name attribute) *display-attributes*)))
+  (description-class-attributes (class-of description)))
+
+(defun description-current-attributes (description)
+  	  (remove-if-not 
+	   (lambda (attribute)
+	     (and 		     
+	      (some #'layer-active-p 
+			(mapcar #'find-layer 
+				(slot-definition-layers 
+				 (attribute-effective-attribute-definition attribute))))))
+	   (description-attributes description)))
+
+(defun description-active-attributes (description)
+  	  (remove-if-not 
+	   #'attribute-active-p
+	   (description-attributes description)))
+
+(defun find-attribute (description attribute-name &optional (errorp t))
+  (or (find attribute-name (description-attributes description)
+	    :key #'attribute-name)
+      (when errorp (error "No attribute named ~A found in ~A" attribute-name description))))
+
+(define-layered-function description-active-descriptions (description)
+  (:method ((description standard-description-object))
+    (attribute-value (find-attribute description 'active-descriptions)))
+  (:method ((description attribute))
+    (attribute-active-descriptions description)))
+
+(define-layered-function description-inactive-descriptions (description)
+  (:method ((description standard-description-object))
+    (attribute-value (find-attribute description 'inactive-descriptions)))
+  (:method ((description attribute))
+    (attribute-inactive-descriptions description)))
 
 (define-layered-function attributes (description)
   (:method (description)
-    (remove-if-not 
-     (lambda (attribute)
-       (and (attribute-active-p attribute)
-	    (some #'layer-active-p 
-	     (mapcar #'find-layer 
-		     (slot-definition-layers 
-		      (attribute-effective-attribute-definition attribute))))))
-     (description-attributes description))))
-
-  
-;;; A handy macro.
+    (let* ((active-attributes 
+	    (find-attribute description 'active-attributes))
+	   (attributes (when active-attributes
+			 (ignore-errors (attribute-value active-attributes)))))
+      (remove-if-not 
+       (lambda (attribute)
+	 (and attribute
+	      (attribute-active-p attribute)		     
+	      (some #'layer-active-p 
+		    (mapcar #'find-layer 
+			    (slot-definition-layers 
+			     (attribute-effective-attribute-definition attribute))))))
+       (if attributes
+	   (mapcar (lambda (spec)		    
+		     (find-attribute 
+		      description
+		      (if (listp spec)
+			  (car spec)
+			  spec)))
+		   attributes)
+	   (description-attributes description))))))
+	  
+
+(defun funcall-with-described-object (function object description &rest args)
+  (setf description (or description (description-of object)))
+  (let ((*description* description)
+	(*object*  object))
+    (dletf (((described-object *description*) object))
+	(funcall-with-layer-context
+	 (modify-layer-context 
+	  (if (standard-description-p *description*)
+	      (adjoin-layer *description* (current-layer-context))
+	      (current-layer-context))
+	  :activate (description-active-descriptions *description*)
+	  :deactivate (description-inactive-descriptions *description*))
+	 (lambda () (contextl::funcall-with-special-initargs  
+		     (loop 
+			:for (key val) :on args :by #'cddr
+			:collect (list (find key (description-attributes *description*) 
+					     :key #'attribute-keyword)
+				       :value val))
+		     (lambda ()
+		       (contextl::funcall-with-special-initargs  
+			(let ((attribute (ignore-errors (find-attribute *description* 'active-attributes))))	
+			  (when attribute
+			    (loop for spec in (attribute-value attribute)
+			       if (listp spec)
+			       collect (cons (or 
+					      (find-attribute *description* (car spec))
+					      (error "No attribute matching ~A" (car spec)))
+					     (cdr spec)))))
+			function))))))))
+
+
+(defmacro with-described-object ((object description &rest args)
+				 &body body)
+    `(funcall-with-described-object 
+      (lambda () ,@body)
+      ,object
+      ,description
+      ,@args))
+		   
 (defmacro define-description (name &optional superdescriptions &body options)
   (let ((description-name (defining-description name)))     
     (destructuring-bind (&optional slots &rest options) options