Re: bash completion with colour hints

From: Simon Oosthoek <soosthoek@nieuwland.nl>
Date: Sep 27, 2012, 09:16 UTC
Message-ID: <50641989.6060001@nieuwland.nl>
In-Reply-To: <5064140E.50007@drmicha.warpmail.net>

On 09/27/2012 10:53 AM, Michael J Gruber wrote:

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>> We do not usually add new features to maintenance tracks, so the
>> result of applying the patch does not have to be merge-able to maint
>> or amything older.  I would base the patch on v1.7.12 (the latest
>> stable release) if I were you.
>>

I now have a patch based on 1.7.12

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>>> - I read that git-prompt.sh is meant to support bash and zsh, I have
>>> only tested it on bash. Should I attempt to test it on zsh or is there a
>>> kind person with zsh as his/her shell to test it for me?
>
> Actually, the instructions in the prompt script are not complete for zsh
> (you need to activate expansion in the prompt), and I think there is
> some breakage because bash uses "\h" etc. for PS1 format specifiers
> whereas zsh uses '%h', and so the '%' in the prompt is a problem for zsh.

The only feature using it is untracked files, so that should probably be changed to work with zsh?

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>
> Additionally, there have been several attempts already for prompt. So
> I'd suggest you check the list archives to see whether you addressed the
> issues which were raised back then. I've actually been toying with that
> myself lately. A few hints:

This would take me too much time

>
> - You need to escape the escapes '\[', i.e. tell the shell that color
> escapes produce zero length output, or else line wrapping is distorted.

A: this is something I've run into with my own contraption and I'm not 
sure I fixed it with my patch :-(

Can you give a more complete example of how that should work?

>
> - Bash interpretes '\' only when PS1 is assigned, not when an expansion
> in PS1 produces it.

is that true? how can \w produce the current working dir in the prompt? Or do you mean it is translated to $PWD in some form internally?

>
> - Some don't like it colorful, so the coloring needs to depend on a
> config setting or env variable.

It is.

>
> - Coloring should be consistent with other coloring in Git, such as
> 'status -s -b'.

That would be nice, I suppose the coloring is configurable for git, so the values would need to be dynamically imported from the git config. I don't know how to do that.

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>
> - Coloring provides the way to make the prompt characters analogous to
> 'status -s -b' because a green 'M' is different from red 'M', and is
> much clearer then having to remember '+' vs. '*' (so there is a logic in
> that).

Are you suggesting to use M instead of * or +? wouldn't that interfere with branchnames?

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>
>  From trying myself, I'm convinced that you need a clever combination of
> PROMPT_COMMAND and PS1 to make this work. Setting PS1 in PROMPT_COMMAND
> is probably a no-go because that makes it difficult to customize PS1. I
> have something in the works which reproduces the current prompt but need
> to clean it up further. The actual coloring would require setting a lot
> of variables which communicate data from PROMPT_COMMAND to PS1, and I
> actually don't like that.

I think it should be possible in PS1 only.

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>
> An alternative approach would be:
>
> - Tell users to activate git prompt by doing something like
>
> PROMPT_COMMAND='__git_prompt "[\u@\h \W (%s)]\$ '
>
> rather than the current
>
> PS1='[\u@\h \W$(__git_ps1 " (%s)")]\$ '
>
> - set PS1 from __git_prompt
>
> I'm not sure about the performance implications of re-setting PS1 on
> (before) each prompt invocation, though. Would that be OK?

I doubt you can set PS1 from a function (effectively a subshell?)

Thanks for your comments

I will send an updated patch later....

/Simon