rewrite world/player state tracking (#453)

1 files changed, 15 insertions, 0 deletions

diff --git a/src/SMAPI/Framework/StateTracking/IValueWatcher.cs b/src/SMAPI/Framework/StateTracking/IValueWatcher.cs
new file mode 100644
index 00000000..4afca972
--- /dev/null
+++ b/src/SMAPI/Framework/StateTracking/IValueWatcher.cs
@@ -0,0 +1,15 @@
+namespace StardewModdingAPI.Framework.StateTracking
+{
+    /// <summary>A watcher which tracks changes to a value.</summary>
+    internal interface IValueWatcher<out T> : IWatcher
+    {
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>The field value at the last reset.</summary>
+        T PreviousValue { get; }
+
+        /// <summary>The latest value.</summary>
+        T CurrentValue { get; }
+    }
+}