Re: [PATCH 2/2] emacs: Add shell completions for "guix" command.

[Alex Kost]

Ludovic Courtès (2015-06-07 18:36 +0300) wrote:

> Alex Kost <address@hidden> skribis:
>
>> It should complete almost everything except suboptions of subcommands, I
>> mean those ‘import’ modules (e.g., it will not complete
>> ‘--no-test-dependencies’ option for ‘guix import hackage’ command).
>
> I think that’s fine.  We wouldn’t want to maintain relatively custom
> completion code for all these things anyway.
>
> However it’s important to fall back to file name completions for things
> that are not handled, so that at least it is not worse than without the
> pcomplete code.

Yes, it is the current behaviour (I mean the file names completion).

>> Completing may lag a bit from time to time.  It happens because shell
>> commands (like ‘guix ... --help’) are called when necessary to find
>> options, packages, etc.  But the found entries are "memoized" so next
>> time the same entries will be completed much faster.
>
> I wonder if ‘guix-pcomplete-run-guix’ couldn’t run the command in a REPL
> instead of spawning a process.  That is, when completing ‘guix build’,
> it would evaluate something like:
>
>   (with-output-to-string
>     (lambda ()
>       (catch 'quit
>         (lambda ()
>           ((@ (guix scripts build) guix-build) "--help"))
>         (const #t))))
>
> How does that sound?

It was the initial deliberate decision to separate completions code from
interacting with "guix repl", to make completing independent.  I imagine
that a user wouldn't like to see that some "Guix REPL has been started"
just because he presses TAB after ‘guix pa’ in his shell buffer.  Well,
at least I wouldn't use such strange completions.

I think lags made by spawning the guix processes are bearable and not
repeatable (I mean the next time ‘guix pa’<TAB> is completed
immediately), so I would not like to change the code to use a REPL if
you don't mind :-)

(Perhaps in the future there will be added some option (e.g., a boolean
`guix-pcomplete-use-repl' variable) to choose what a user prefers)

>> Many thanks to Ludovic for the great idea of this package!
>
> Well I’m always impressed by your productivity!

Thanks, but it is far from yours!!

>> From 9ed30b97519afad84c58f1a7166f11a5e22ecda1 Mon Sep 17 00:00:00 2001
>> From: Alex Kost <address@hidden>
>> Date: Sat, 6 Jun 2015 22:19:51 +0300
>> Subject: [PATCH 2/2] emacs: Add shell completions for "guix" command.
>>
>> * emacs/guix-pcomplete.el: New file.
>> * emacs.am (ELFILES): Add it.
>> * doc/emacs.texi (Emacs Completions): New node.
>
> LGTM!  OK to push.
[...]
>> +     ((and (command? "publish")
>> +           (option? "-u" "--user"))
>> +      (complete* (pcmpl-unix-user-names)))
>> +
>> +     ((and (command? "refresh")
>> +           (option? "-s" "--select"))
>> +      (complete* guix-pcomplete-refresh-subsets)))))
>
> I like that this is very accurate.  I was first slightly concerned about
> the risk of this becoming out of sync, but I think we’d quickly notice
> and it seems easy to update anyway.

Yes, I think we'll notice, thanks.

I have pushed this commit, so if someone notices that something is not
completed properly, please report.

-- 
Alex