Re: Add colors to the prompt for status indicators

From: Kevin Ballard <kevin@sb.org>
Date: Nov 16, 2010, 10:49 UTC
Message-ID: <5FCB4CFB-65F1-4694-AFB4-36A9612BE4F3@sb.org>
In-Reply-To: <4CE2603D.8080209@drmicha.warpmail.net>

On Nov 16, 2010, at 2:43 AM, Michael J Gruber wrote:

Show 37 quoted lines

> Kevin Ballard venit, vidit, dixit 16.11.2010 10:07:
>> On Nov 16, 2010, at 12:11 AM, Sebastien Douche wrote:
>> 
>>> On Tue, Nov 16, 2010 at 00:14, Kevin Ballard <kevin@sb.org> wrote:
>>>> I take it back. We can use PROMPT_COMMAND for this, to set up variables
>>>> containing what you want.
>>>> 
>>>> Something like the following should work:
>>> 
>>> Hi Kevin,
>>> good job! I looked the git prompt and I'm a bit disappointed with the
>>> combination, ps1 can show many items:
>>> 
>>> #
>>> %
>>> +
>>> *
>>> $
>>> REBASE-i|
>>> REBASE-m|
>>> MERGING|
>>> BISECTING|
>>> < > <> (or u+count u-count u+countu-count)
>>> 
>>> Each item is "optional", so you can have REBASE-i| with * and +, or
>>> only *. It seems to complicated to wrap all items (I think of the
>>> verbose mode for upstream branches). Maybe coding a lua (or Python)
>>> prompt with a config file.
>> 
>> In the end you need to stuff everything that needs a distinct color into its
>> own shell variable. You could just extend the shell function that's doing that
>> right now, or you could write a script in another language that emits a
>> shell-quoted set of variables suitable for evaling by the shell.
> 
> Also, you should get away from parsing individual characters in
> __git_ps1. Characters like + and - are valid in branch names. Coloring
> them within the name is not quite intended.

That's actually handled with the PROMPT_COMMAND version. It uses

  git rev-parse --symbolic-full-name --abbrev-ref=loose HEAD

to get a copy of the branch name, and then removes that from the __git_ps1 output. Everything that's left is part of the status.

> I guess the only way is to produce colors within __git_ps1 (based on an
> option). Also, colors would allow to use the same status letters as "git
> status -s".

That's how my original version worked (though it had the flaw you mentioned above). The PROMPT_COMMAND version was motivated by the fact that the color escapes need to be embedded directly in PS1 so \[ and \] can be used to instruct bash to treat them as non-printable characters. If the color codes are emitted by __git_ps1 directly, then bash will incorrectly treat them as printable characters and wrap at the wrong spot.

What would be nice is a mode for __git_ps1 that emits a string suitable for eval by bash that gives every status indicator its own variable. This could be enabled by using something like $(__git_ps1 --shell-quote " (%s)"). In this case, __git_ps1 would break the format string into two parts, by splitting around the %s, and put those in the left/right guard variables.

-Kevin Ballard