More work on variables

Yc/Program.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using Upsilon;
+using Upsilon.Binder;
 using Upsilon.Evaluator;
 
 namespace Yc
@@ -10,7 +11,7 @@ namespace Yc
         static void Main(string[] args)
         {
             Console.WriteLine("Upsilon REPL");
-            Dictionary<string, object> variables = new Dictionary<string, object>();
+            Dictionary<VariableSymbol, object> variables = new Dictionary<VariableSymbol, object>();
             while (true)
             {
                 Console.Write("» ");
@@ -20,7 +21,7 @@ namespace Yc
                     return;
                 }
 
-                var parsed = new Script(input);
+                var parsed = new Script(input, variables);
                 if (parsed.Diagnostics.Messages.Count > 0)
                 {
                     Console.ForegroundColor = ConsoleColor.Red;