Re: Completion script for the ctags program

[Jacob Gelbman <gelbman@xxxxxxxxx>]

Hey, thanks for looking at the script and adding it to the repo, although I think some of got pasted in wrong. There’s a lot to writing completion functions and I’m still not 100% sure how to do it right.

> On Feb 23, 2021, at 3:39 PM, Oliver Kiddle <opk@xxxxxxx> wrote:
> 
> Jacob Gelbman wrote:
>> I wrote a completion script for the ctags program. Someone might be able to use it:
> 
> Which ctags!?

I have Universal Ctags 5.9.0

> This doesn't match what I have installed on any of my systems. There
> are multiple implementations of ctags, with it often being just a link
> to etags - for which there is a completion albeit not a well maintained
> one. One of the main reasons, a completion doesn't already exist is
> that it would ideally need to detect the variant and at least have sane
> fallbacks for variants that aren't handled. It could be useful to check
> what the existing _etags is handling - that might be the exhuberant or
> emacs variant.
> 

I located a few other ctags on my computers, I have BSD ctags that comes by default on the mac. Exuberant Ctags 5.8. and there’s etags that comes with emacs. I can probably add an if statement based on the output of ctags —version, and modify the function from that. If it’s etags, I’ll just:

_comps[ctags]=“_etags”; _etags

And exit.

> In general, please follow the conventions outlined in
> Etc/completion-style-guide in the zsh source distribution. For example,
> completion functions usually use just 2 spaces for indentation.
> 
>> #compdef ctags
>> 
>> local state
> 
> If you use states, you need to also handle the context which means
> either passing -C to _arguments and setting up $curcontext or declaring
> context local and passing it to later functions like _values.

The -C argument and the context/curcontext variables are confusing me, a lot.

> 
>>    "--alias-<lang>=[add a pattern detecting a name, can be used as an alt name for lang]:pattern" \
>>    "--input-encoding-<lang>=[specify encoding of the <lang> input files]:encoding" \
>>    "--kinddef-<lang>=[define new kind for <lang>]:kind" \
>>    "--kinds-<lang>=[enable/disable tag kinds for <lang>]:kind" \
> 
> These would not complete especially helpfully. I suspect that <lang> there is
> supposed to be substituted.

They’d show up in the menu when you press tab, but if I filled in the actual values, the list would be too long.

> 
>> if [ "$state" = "language" ]; then
>>    compadd `ctags --list-languages | cut -d" " -f1`
> 
> It would be nicer to use a description by calling for example, _wanted
> here.

I can do that.

> 
>> elif [ "$state" = "languages" ]; then
>>    _values -s , "languages" `ctags --list-languages | cut -d" " -f1`
>> fi
> 
> I'd probably use _sequence here as it is smaller and simpler. But
> _values is fine if none of the languages contain characters that need
> quoting from it.

This too.

> 
> The return status from this function will not be correct in all cases.
> This can have effects like approximate completion being activated
> despite matches having been added by earlier completers. Where states
> are needed, you nearly always need to either save the status from
> _arguments, typically via a ret variable or check $compstate[nmatches]
> on exit.
> 
> Oliver