Using Eclipse or Xtext for Unity Javascript?

Has anyone configured Eclipse Xtext as an ide for use with Unity Javascript

Ideally (minimally) - code completion

and also inline help

You can use any editor you'd like.

To set the default script editor, change the drop-down item in Unity->Preferences->External Script editor.

From: http://unity3d.com/support/documentation/Manual/Scripting.html

Good luck!