check group in when toggling same ids

[tmatias]

Currently, ToggleSameIds doesn't check the group of the match and, as I set up vim to highlight characters that go beyond column 80 (just find it a mostly helpful heuristic), when I open a file that contains longer lines, ToggleSameIds always try to clear highlighted ids, because getmatches() return all highlights and not just the GoSameId ones.

So, as already done in ClearSameIds, I think we should also test the group here.

[bhcleek]

Thank you for the contribution.

go#guru#ClearSameIds, which is called by go#guru#ToggleSameIds, already checks the group and only clears matches that are in the goSameId group. See https://github.com/fatih/vim-go/blob/master/autoload/go/guru.vim#L537-L542.

[tmatias]

@bhcleek you are correct about that.

However, ToggleSameIds itself does not and so, if there are any matches, even if not in the goSameId group, it will always decide that it should call ClearSameIds and therefore the toggling won't work as expected.

(see PR description :P)

[bhcleek]

I see. In that case, instead of repeating the logic for iterating through the matches, go#guru#ClearSameIds should return a non-zero value when no matches were found and that value should be checked in go#guru#ToggleSameIds, which should call go#guru#SameIds if no goSameId groups where cleared. Will you refactor to do that?

[tmatias]

That sounds like a better approach. Thank you.

I'll do that.

[tmatias]

Returned a positive value for success and zero for the other case, but I can change that to return a negative value if it would make things better. (Not knowing much vimscript, it just seemed nicer.)

[bhcleek]

Yes, please invert the return value; conventionally 0 is success, and non-zero is failure. Since go#guru#ClearSameIds is supposed to delete any goSameId groups, failure should mean that none were removed.

[bhcleek]

If no matches were in the goSameId group, then return early here so that the BufWinEnter events won't be removed.

[bhcleek]

Thank you!

[bhcleek]

Thank you for contributing. I squashed your commits and merged them into master.