Probs with nested braces in PROMPT

Probs with nested braces in PROMPT

[Bernd Eggink]

Are nested braces supposed to work in PROMPT (zsh 3.1.9-dev-2)? 
I tried this:

PROMPT='%{^[[5;46m%}%m:%l %T %~${PROJECT:+ %{^[[31m[%}}$PROJECT${PROJECT:+]%{^[[30m%}}%#%{^[[0m%}'

which looks good if PROJECT is set, for example with PROJECT=ecc:

    eggink3:1 11:25 ~/necht [ecc]%

(actually nicely coloured). However, when PROJECT is not set, it results
in something ugly:

    eggink3:1 11:26 ~/necht}}%

Bug or feature?

Regards,
Bernd

-- 
Bernd Eggink
Regionales Rechenzentrum der Uni Hamburg
eggink@uni-hamburg.de
http://www.rrz.uni-hamburg.de/eggink/BEggink.html

RE: Probs with nested braces in PROMPT

[Andrej Borsenkow]

>
> PROMPT='%{^[[5;46m%}%m:%l %T %~${PROJECT:+
> %{^[[31m[%}}$PROJECT${PROJECT:+]%{^[[30m%}}%#%{^[[0m%}'
>

You do have promptsubst set, don't you?

What about

PROMPT='%{^[[5;46m%}%m:%l %T %~${PROJECT:+
%{^[[31m[%\}}$PROJECT${PROJECT:+]%{^[[30m%\}}%#%{^[[0m%}'

(note, that `}' in %} are quoted). This seems to work. I suspect, why it
happens, but I do not know code good enugh.

-andrej

Re: Probs with nested braces in PROMPT

[Peter Stephenson]

Andrej wrote:
> >
> > PROMPT='%{^[[5;46m%}%m:%l %T %~${PROJECT:+
> > %{^[[31m[%}}$PROJECT${PROJECT:+]%{^[[30m%}}%#%{^[[0m%}'
> >
>
> What about
> 
> PROMPT='%{^[[5;46m%}%m:%l %T %~${PROJECT:+
> %{^[[31m[%\}}$PROJECT${PROJECT:+]%{^[[30m%\}}%#%{^[[0m%}'
> 
> (note, that `}' in %} are quoted). This seems to work. I suspect, why it
> happens, but I do not know code good enugh.

The problem was that ordinary ${...} doesn't know about %-substitution in
prompts, nor should it (that would be a horrendous complication involving
different levels of substitution).  So it took the brace in `%}' as the
brace closing the substitution.  Andrej's solution is the easiest way
round.  Because of the way parameters are parsed, you could also do

esc1=$'%{\e[31m%}'
esc2=$'%{\e[30m%}'
PROMPT='%{^[[5;46m%}%m:%l %T %~${PROJECT:+
${esc1}[}$PROJECT${PROJECT:+]$esc2}%#%{^[[0m%}'

(replace line break by a space again) which you might consider neater.
You could even put the other escape sequences in that form:  the $'\e'
saves you having literal ASCII escapes in your text.

-- 
Peter Stephenson <pws@cambridgesiliconradio.com>
Cambridge Silicon Radio, Unit 300, Science Park, Milton Road,
Cambridge, CB4 0XL, UK                          Tel: +44 (0)1223 392070

RE: Probs with nested braces in PROMPT

[Andrej Borsenkow]

>
> The problem was that ordinary ${...} doesn't know about
> %-substitution in
> prompts, nor should it (that would be a horrendous
> complication involving
> different levels of substitution).  So it took the brace in
> `%}' as the
> brace closing the substitution.

Yes, of course. But why it did it only when parameter was undefined? I
mean, parsing is done by lexer - and it has to find the closing brace in
any case and lexer does not know (is it true?) about parameter values.

That is incosistent IMHO and smells more like a bug.

-andrej

Re: Probs with nested braces in PROMPT

[Bernd Eggink]

On Thu, Jul 06, 2000 at 01:59:53PM +0400, Andrej Borsenkow wrote:
> >
> > PROMPT='%{^[[5;46m%}%m:%l %T %~${PROJECT:+
> > %{^[[31m[%}}$PROJECT${PROJECT:+]%{^[[30m%}}%#%{^[[0m%}'
> >
> 
> You do have promptsubst set, don't you?
> 
> What about
> 
> PROMPT='%{^[[5;46m%}%m:%l %T %~${PROJECT:+
> %{^[[31m[%\}}$PROJECT${PROJECT:+]%{^[[30m%\}}%#%{^[[0m%}'
> 
> (note, that `}' in %} are quoted). This seems to work. I suspect, why it
> happens, but I do not know code good enugh.

Thanks, this works. My first attempt was to quote both of the braces %\{
...  %\}, but that resulted in something like this:

    eggink3:2 13:01 ~/necht {[ecc]{%

Regards,
Bernd

-- 
Bernd Eggink
Regionales Rechenzentrum der Uni Hamburg
eggink@uni-hamburg.de
http://www.rrz.uni-hamburg.de/eggink/BEggink.html

Re: Probs with nested braces in PROMPT

[Peter Stephenson]

> Yes, of course. But why it did it only when parameter was undefined? I
> mean, parsing is done by lexer - and it has to find the closing brace in
> any case and lexer does not know (is it true?) about parameter values.
> 
> That is incosistent IMHO and smells more like a bug.

No, in that case it got the `%{...%' from inside the braces, then found the
(wrong) closing brace, then found the neglected `}' from the parameter
expansion, therefore getting the complete expression %{...%}.  In this case
it didn't matter which brace was which.

-- 
Peter Stephenson <pws@cambridgesiliconradio.com>
Cambridge Silicon Radio, Unit 300, Science Park, Milton Road,
Cambridge, CB4 0XL, UK                          Tel: +44 (0)1223 392070