We have worked on a tool for converting GraalScript2 to the new Graalscript3 syntax:
http://graalscript3.graalonline.com/
You can use it to test a little bit and see how the new scripting will look like. We plan to release GS3 officially in a few weeks, after improving compatibility and features.
Edit: Updated on June 21 to add better support for global functions and types! You have to restart the npcserver.
Edit: Updated on June 24 to fix object attributes like player.account (TServerPlayer.account), no additional restart required.