Re: Why are prompt expansions of %v sequences quoted in bindkey style?

[Marlon Richert <marlon.richert@gmail.com>]

I missed that a 2nd expansion was needed in my example, but that is easy to work around. 

However, the quoting seems to make it impossible to use $psvar for anything involving control characters.

Is there no way to work around this?

I would like to find a solution that does not involve promptsubst.

> On 23. Jan 2024, at 15.05, Roman Perepelitsa <roman.perepelitsa@gmail.com> wrote:
> 
> On Tue, Jan 23, 2024 at 1:07 PM Marlon Richert <marlon.richert@gmail.com> wrote:
>> 
>> When I declare my prompt as:
>> 
>> PS1=$'%{\e[2m%}%#%{\e[0m%} '
>> 
>> this works as I expect it to: My prompt becomes a dim/faint % followed by a space.
>> 
>> However, this does not work as I expect it to when I store the ANSI sequences in $psvar.
>> 
>> The following code:
>> 
>> psvar=( $'%{\e[2m%}' $'%{\e[0m%}' )
>> PS1='%1v%#%2v '
>> 
>> results in the following prompt with terminal default color:
>> 
>> %{^[[2m%}%%{^[[0m%}
>> 
>> As you can see, the strings stored in $psvar are expanded in a quoted form, à la bindkey.
> 
> Percent expansion isn't recursive. It is done only once. If %v expands
> into %1F, the latter won't be expanded any further and will remain as
> a literal %1F. This behavior makes sense and it alone will preclude
> you from achieving what you are after.
> 
> However, in addition, the expansion of %v is quoted: newline becomes
> \n, escape becomes ^[, etc. This is meant to make the use of %v safe.
> By "safe" I meant that it allows you to ensure a non- broken prompt
> regardless of the content of psvar.
> 
>  # This prompt is never broken: it does not bleed colors,
>  # does not confuse zle w.r.t. the cursor position, etc.
>  PS1='%v%# '
> 
>> Is this intentional?
> 
> I wasn't there when this feature was designed but it works as I would
> expect. If you want an extra percent expansion after the substitution
> of parameters, use prompt_subst. This is a much more powerful and a
> much more dangerous tool.
> 
> Roman.