Support Alias

Author: daxian-dbw

shell/AIShell.Kernel/Command/ClearCommand.cs

@@ -9,6 +9,7 @@ public ClearCommand()
         : base("cls", "Clear the screen.")
     {
         this.SetHandler(ClearAction);
+        this.AddAlias("clear");
     }
 
     private void ClearAction()

shell/AIShell.Kernel/Command/CommandRunner.cs

@@ -57,7 +57,17 @@ internal void LoadCommands(IEnumerable<CommandBase> commands, string agentName)
         {
             command.Shell = _shell;
             command.Source = agentName;
+
+            // TODO: need to think about how to handle command names/aliases collision.
+            // We don't handle collision today -- it will throw when collision happens.
             _commands.Add(command.Name, command);
+            foreach (string alias in command.Aliases)
+            {
+                if (!string.IsNullOrWhiteSpace(alias))
+                {
+                    _commands.Add(alias, command);
+                }
+            }
         }
     }
 
@@ -79,7 +89,16 @@ internal void UnloadAgentCommands()
 
         foreach (var command in agentCommands)
         {
+            // TODO: need to update accordingly when we handle command names/aliases collision.
             _commands.Remove(command.Name);
+            foreach (string alias in command.Aliases)
+            {
+                if (!string.IsNullOrWhiteSpace(alias))
+                {
+                    _commands.Remove(alias);
+                }
+            }
+
             command.Dispose();
         }
     }