From 3b01720d6632674f8e6d72d9adffc3b8a09612b3 Mon Sep 17 00:00:00 2001
From: Ryan Schmidt <rms@rms80.com>
Date: Wed, 10 Oct 2018 13:35:57 -0400
Subject: [PATCH] change-record group

---
 history/SceneChanges.cs | 55 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/history/SceneChanges.cs b/history/SceneChanges.cs
index fcab8ce..eb9b9f4 100644
--- a/history/SceneChanges.cs
+++ b/history/SceneChanges.cs
@@ -397,4 +397,59 @@ public override OpStatus Cull()
         }
     }
 
+
+
+
+    /// <summary>
+    /// Collection of changes that will be applied in-order, and
+    /// reverted in opposite order.
+    /// </summary>
+    public class ChangeSet : BaseChangeOp
+    {
+        List<BaseChangeOp> Changes;
+
+        public override string Identifier() { return "ChangeSet"; }
+
+        public ChangeSet() {
+            Changes = new List<BaseChangeOp>();
+        }
+        public ChangeSet(IEnumerable<BaseChangeOp> all) {
+            Changes = new List<BaseChangeOp>(all);
+        }
+
+        public override OpStatus Apply()
+        {
+            OpStatus totalResult = OpStatus.Success;
+            foreach (var change in Changes) {
+                var result = change.Apply();
+                if (result.code != OpStatus.Success.code)
+                    totalResult = result;
+            }
+            return totalResult;
+        }
+        public override OpStatus Revert()
+        {
+            OpStatus totalResult = OpStatus.Success;
+            int N = Changes.Count;
+            for ( int i = N-1; i >= 0; --i ) {
+                var change = Changes[i];
+                var result = change.Revert();
+                if (result.code != OpStatus.Success.code)
+                    totalResult = result;
+            }
+            return totalResult;
+        }
+        public override OpStatus Cull()
+        {
+            OpStatus totalResult = OpStatus.Success;
+            foreach (var change in Changes) {
+                var result = change.Cull();
+                if (result.code != OpStatus.Success.code)
+                    totalResult = result;
+            }
+            return totalResult;
+        }
+    }
+
+
 }