Re: [PATCH v2] prompt: support generic non-visible regions

[Felipe Contreras <felipe.contreras@xxxxxxxxx>]

On Sun, Aug 14, 2022 at 2:57 PM Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx> wrote:
>
> On Thu, Aug 11, 2022 at 4:09 PM Felipe Contreras
> <felipe.contreras@xxxxxxxxx> wrote:
> >
> > readline uses \001 (start of header) and \002 (start of text) as markers
> > to delimit a non-visible character zone, which are necessary to
> > calculate the width of a prompt.
>
> How does one embed a literal ctrl-A or ctrl-B in the prompt?

What would that achieve?

> I haven't found any readline documentation that explains the use of
> "start of header" or "start of text".

It's in the code:

https://git.savannah.gnu.org/cgit/readline.git/tree/display.c#n340

> I'm also leaning to the opinion that \001 and \002 should only be
> recognized when PROMPT_PERCENT is unset.

That would defeat the primary purpose of the patch, which is to be
able to write prompt helper functions which work in multiple shells.

-- 
Felipe Contreras