This oneliner is ready for reviewing. It works excellent with the interpreters i've been using and really improves the UX perception.
But I wonder if there are interpreters (python?) for which the (tab) key is preferred to act as tab rather an auto-completion shortcut?

Thanks. I've tested this branch and the feature itself working well.
However, depends on language, TAB is not ideal for some language like python or scala. (for them '.' is more appropriate i think).

I think code editor need to get some informations from interpreter. Not only keyboard shortcuts for completion, but also like syntax highlight scheme and many more.

+1 @Leemoonsoo https://issues.apache.org/jira/browse/ZEPPELIN-214
I think we should be good with this PR and track the bigger work on interpreter environment settings in a JIRA.

+1 to get syntax highlight for editor.
Since we can add new interpreters to zeppelin. It is important add plug auto-completion (js-hint) for editors.

Architecture of the auto-completion of editor need to extend-able as we have multiple interpreters.

@Leemoonsoo i expected that some interpreters would prefer to retain the tab key as a tab.

@felixcheung, to have this PR accepted and should i close it unresolved?

There are couple of other auto-completion related improvements like ZEPPELIN-139 , ZEPPELIN-214 that address the ability of the Interpreter to decides the ACE modes (and related highlight / completion features). Those though are dependent on ZEPPELIN-219 at the moment.

@Leemoonsoo @felixcheung @tzolov shall we update this one and merge or close it?

@tzolov Thanks for your work on this. Are you still working on this? What is needed to complete this one?

@tzolov Should we close this one?