Re: Supporting %F{...} and %K{...} in Zsh 4.x

[Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx>]

On Sun, Dec 17, 2023 at 11:43 AM Grant Taylor
<gtaylor@xxxxxxxxxxxxxxxxxx> wrote:
>
> Does anyone have any better ideas on how to support %F / %f and %K / %k
> in Zsh 4.2.5?

That seems like an awful lot of work to go through for something that
doesn't change very often.  Why not just something like:

if [[ "${(%):-"%F{red}%f"}" = *red* ]]
then PROMPT=$'This is an %{\e[31m%}old%{\e[39m%} shell %# '
else PROMPT='This is a %F{red}new%f shell %# '
fi

I'm pretty sure $'...' works properly in 4.2.5, but the closest I can
test with is 4.2.6.  In sufficiently old zsh, even the parse of
"${(%):-"%F{red}%f"}" doesn't work.

> export PROMPT=${PROMPT//\%f/%{^[[39m%}}
> export PROMPT=${PROMPT//\%F{black}/%{^[[30m%}}
[...]

What Roman said RE "export".

Also there's no reason to re-export a parameter every time you change
it.  Once exported, always exported, unless "typeset +x" is used.