Refactor update pipelines

1 files changed, 11 insertions, 7 deletions

diff --git a/world.scm b/world.scm
index 14840c8..de9027c 100644
--- a/world.scm
+++ b/world.scm
@@ -45,7 +45,7 @@
     (update-scene scene
       entities: (append (scene-entities scene) (list entity))))
 
-  (define (scene-update-entities scene . procs)
+  (define (scene-map-entities scene . procs)
     "Apply each proc in sequence to the scene's entities; returns a new scene."
     (update-scene scene
       entities: (fold (lambda (proc es) (map proc es))
@@ -57,6 +57,11 @@
     (update-scene scene
       entities: (filter pred (scene-entities scene))))
 
+  (define (scene-transform-entities scene proc)
+    "Apply proc to the full entity list (entities → entities); returns a new scene."
+    (update-scene scene
+      entities: (proc (scene-entities scene))))
+
   ;; Center camera on entity. Clamps to >= 0 on both axes.
   ;; Returns a new camera struct.
   (define (camera-follow camera entity viewport-w viewport-h)
@@ -105,10 +110,9 @@
                                (entity-ref e #:group-local-y 0))))
           e)))
 
-  ;; Snap member #:x/#:y to origin + #:group-local-x/y. Returns a new scene.
-  (define (scene-sync-groups scene)
-    (let ((origins (group-origin-alist (scene-entities scene))))
-      (update-scene scene
-        entities: (map (cut sync-member-to-origin <> origins)
-                       (scene-entities scene)))))
+  ;; Snap member #:x/#:y to origin + #:group-local-x/y.
+  ;; Pure entities → entities function; use with scene-transform-entities.
+  (define (sync-groups entities)
+    (let ((origins (group-origin-alist entities)))
+      (map (cut sync-member-to-origin <> origins) entities)))
 )