ZEPPELIN-277: Set the (TAB) key as an auto-completion shortcut

[tzolov]

Oneliner fix that:

• Sets (TAB) as the main auto-completion shortcut key.
• Keeps the existing (Ctrl+.) shortcut for backward compatibility. We should define some deprecation period (0.6.0 release perhaps?)

[tzolov]

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?

[Leemoonsoo]

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.

[felixcheung]

+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.

[Madhuka]

+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.

[tzolov]

@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.

[bzz]

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

[vinayshukla]

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

[corneadoug]

@tzolov Should we close this one?