1 files changed, 10 insertions(+), 1 deletions(-)

M fairy.lisp

@@ 32,6 32,7 @@
            height
 
            layer
+           sort-with
            boundary
            add-child
            get-child


@@ 132,7 133,10 @@
              :accessor children)
    (boundary :initarg :boundary
              :initform nil
-             :accessor boundary)))
+             :accessor boundary)
+   (sort-with :initarg :sort-with
+              :initform nil
+              :accessor sort-with)))
 
 (defdraw (el layer)
     (with-slots (boundary children) el


@@ 155,6 159,11 @@
         value))
 
 (defmethod update ((el layer) dt)
+  (when (sort-with el)
+    (sort (children el)
+          (sort-with el)
+          :key #'cdr))
+
   (dolist (e (children el))
     (update (cdr e) dt))
   (call-next-method))