Adding completion extension loading and execution logic

[shengyfu]

No description provided.

[coveralls]

Coverage increased (+0.09%) to 71.513% when pulling 0d96f7d on shengyfu:shengyfu-jun27 into e3ec6eb on microsoft:master.

[Charles-Gagnon]

Overall it's looking good! Some changes I'd like to see made though and I'd like @kevcunnane to also do a quick run-over to see if the MEF stuff looks good but I think we're definitely getting there.

[Charles-Gagnon]

Note that the CI build is failing - looks like it can't build your CompletionExtSample project. Make sure you investigate and get that fixed before checkin. #Closed

[shengyfu]

@kevcunnane , did you get a chance to review the latest code? @Charles-Gagnon , let me know when I can merge the change to master? #Closed

[kburtram]

Looks good to me. I'll wait for @Charles-Gagnon to sign-off prior to merging since he has a number of comments pending.

[shengyfu]

@kburtram, I added a list of TSQL functions into the default completion list, please review.

[kburtram]

I think adding built-in SQL functions is fine. Though I'm not sure how effective it will be. The way the IntelliSense works is that we first try to use the T-SQL parser to get suggestions. The parser will only provide schema-based suggestions (unfortunately it doesn't support keyword suggestions). Only if there are no schema-based suggestions then we return this default keyword list.

I suspect that most the code locations where a user would want to call a function they will likely have schema suggestions available (e.g. in column lists, where clauses, having clauses, etc). So the default completion list would not be provided.

There are couple exceptions, such as when the editor is not connected or when no tables have been listed in the from clause yet. But I suspect in the most common use-cases the functions still won't be suggested. Overall, I'm still fine adding them though in case they help in some cases.

[shengyfu]

I see, the TSQL functions should merge with the schema-based suggestions after a space or comma.

[Charles-Gagnon]

Overall looks good but I'd still like to see you add more tests - especially for the assembly loading logic.