scene: Use pushdown state.

1 files changed, 13 insertions, 15 deletions

diff --git a/catbird/scene.scm b/catbird/scene.scm
index 46d343e..445a66c 100644
--- a/catbird/scene.scm
+++ b/catbird/scene.scm
@@ -25,6 +25,7 @@
   #:use-module (catbird mixins)
   #:use-module (catbird mode)
   #:use-module (catbird node)
+  #:use-module (catbird pushdown)
   #:use-module (chickadee data array-list)
   #:use-module (chickadee scripting)
   #:use-module (ice-9 exceptions)
@@ -49,9 +50,7 @@
 
 (define-root-class <scene> (<node>)
   (regions #:accessor regions #:init-value '())
-  (major-mode #:accessor major-mode #:init-keyword #:major-mode
-              #:init-form (make <nothing-mode>))
-  (major-mode-stack #:getter major-mode-stack #:init-thunk make-array-list)
+  (major-mode-state #:getter major-mode-state #:init-thunk make-pushdown-state)
   (minor-modes #:accessor minor-modes #:init-value '())
   (input-map #:getter input-map #:init-value '()))
 
@@ -75,13 +74,16 @@
 (define-method (initialize (scene <scene>) args)
   (next-method)
   (with-scene scene
-    (attach (major-mode scene) scene)))
+    (replace-major-mode scene (make <nothing-mode>))))
+
+(define-method (major-mode (scene <scene>))
+  (state-current (major-mode-state scene)))
 
 (define-method (replace-major-mode (scene <scene>) (mode <major-mode>))
   (let ((old-mode (major-mode scene)))
     (when old-mode
       (detach old-mode))
-    (set! (major-mode scene) mode)
+    (state-replace! (major-mode-state scene) mode)
     (attach mode scene)))
 
 (define-method (replace-major-mode (mode <major-mode>))
@@ -89,24 +91,20 @@
 
 (define-method (push-major-mode (scene <scene>) (mode <major-mode>))
   (let ((old-mode (major-mode scene)))
-    (array-list-push! (major-mode-stack scene) old-mode)
     (when old-mode
       (pause old-mode))
-    (set! (major-mode scene) mode)
+    (state-push! (major-mode-state scene) mode)
     (attach mode scene)))
 
 (define-method (push-major-mode (mode <major-mode>))
   (push-major-mode (current-scene) mode))
 
 (define-method (pop-major-mode (scene <scene>))
-  (let ((stack (major-mode-stack scene)))
-    (unless (array-list-empty? stack)
-      (let ((mode (major-mode scene))
-            (prev-mode (array-list-pop! stack)))
-        (when mode
-          (detach mode))
-        (set! (major-mode scene) prev-mode)
-        (resume prev-mode)))))
+  (when (state-previous (major-mode-state scene))
+    (let ((mode (major-mode scene)))
+      (when mode
+        (detach mode))
+      (resume (state-pop! (major-mode-state scene))))))
 
 (define-method (pop-major-mode)
   (pop-major-mode (current-scene)))