Cache S7 variable names

Sharp7.Rx/CacheVariableNameParser.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Collections.Concurrent;
+using Sharp7.Rx.Interfaces;
+
+namespace Sharp7.Rx
+{
+    internal class CacheVariableNameParser : IS7VariableNameParser
+    {
+        private static readonly ConcurrentDictionary<string, S7VariableAddress> addressCache = new ConcurrentDictionary<string, S7VariableAddress>(StringComparer.OrdinalIgnoreCase);
+
+        private readonly IS7VariableNameParser inner;
+
+        public CacheVariableNameParser(IS7VariableNameParser inner)
+        {
+            this.inner = inner;
+        }
+
+        public S7VariableAddress Parse(string input) => addressCache.GetOrAdd(input, inner.Parse);
+    }
+}