From 3731f442ca40619ce7e62789e6b8c44571866e74 Mon Sep 17 00:00:00 2001
From: Thomas White <taw@physics.org>
Date: Sun, 10 Jul 2022 14:57:12 +0200
Subject: Add "state-empty?"

---
 guile/starlet/state.scm |  8 +++++++-
 guile/starlet/utils.scm | 14 +++++++++++++-
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/guile/starlet/state.scm b/guile/starlet/state.scm
index 0fff383..0047014 100644
--- a/guile/starlet/state.scm
+++ b/guile/starlet/state.scm
@@ -57,7 +57,8 @@
             value->number
             atomically-overlay-state!
             update-state!
-            add-update-hook!))
+            add-update-hook!
+            state-empty?))
 
 
 ;; A "state" is an atomically-updating container for an immutable
@@ -452,3 +453,8 @@ pre-existing contents."
           (set! selection (flatten-sublists fixture-list))))
   (run-hook selection-hook selection))
 
+
+(define (state-empty? st)
+  (hash-table-empty?
+    (atomic-box-ref
+      (get-ht-box st))))
diff --git a/guile/starlet/utils.scm b/guile/starlet/utils.scm
index 7656827..4a2f0be 100644
--- a/guile/starlet/utils.scm
+++ b/guile/starlet/utils.scm
@@ -22,6 +22,7 @@
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-8)
   #:use-module (ice-9 exceptions)
+  #:use-module (ice-9 control)
   #:export (print-hash-table
             copy-hash-table
             in-range
@@ -38,7 +39,8 @@
             scale-and-clamp-to-range
             percent->dmxval8
             percent->dmxval16
-            comment))
+            comment
+            hash-table-empty?))
 
 
 (define (print-hash-table ht)
@@ -166,3 +168,13 @@
   (syntax-rules ()
     ((_ body ...)
      #f)))
+
+
+(define (hash-table-empty? ht)
+  (let/ec
+    return
+    (hash-for-each-handle
+      (lambda (key)
+        (return #f))
+      ht)
+    #t))
-- 
cgit v1.2.3