$? being clobbered?

$? being clobbered?

[Phil!Gregory]

I'm having a problem with zsh, and am not sure if it's a bug or a
feature.  If I have a program executed in my prompt, its return status
clobbers the value of $?, which isn't really what I want.  Example:

> PROMPT='> '
> perl -e 'exit 42'
> echo $?
42
> PROMPT='%{$(echoti cub 80)%}> '
> perl -e 'exit 42'
> echo $?
0

Is there some way to fix this?

(zsh 4.0.7, Sven.)

-- 
...computer contrarian of the first order... / http://aperiodic.net/phil/
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Re: $? being clobbered?

[Michał Politowski]

On Mon, 14 Jul 2003 13:35:56 -0400, Phil!Gregory wrote:
> I'm having a problem with zsh, and am not sure if it's a bug or a
> feature.  If I have a program executed in my prompt, its return status
> clobbers the value of $?, which isn't really what I want.  Example:
> 
> > PROMPT='> '
> > perl -e 'exit 42'
> > echo $?
> 42
> > PROMPT='%{$(echoti cub 80)%}> '
> > perl -e 'exit 42'
> > echo $?
> 0
> 
> Is there some way to fix this?

You can hack around this with
$(R=$?;echoti cub 80;return $R)

-- 
Michał Politowski -- mpol@charybda.icm.edu.pl
Warning: this is a memetically modified message

Re: $? being clobbered?

[Bart Schaefer]

On Jul 14,  1:35pm, Phil!Gregory wrote:
} Subject: $? being clobbered?
}
} I'm having a problem with zsh, and am not sure if it's a bug or a
} feature.  If I have a program executed in my prompt, its return status
} clobbers the value of $?, which isn't really what I want.

There's code in the precmd handler to preserve and restore $? but nothing
similar is done during prompt expansion.

Is there some reason to execute the command every time the prompt is
printed?  That is, does the command change from one prompt to the next?
If not, I suggest:

    unsetopt promptsubst
    PROMPT="%{$(echoti cub 80)%}> "	# Note double quotes

Otherwise I suggest using precmd:

    unsetopt promptsubst
    PROMPT='> '
    function precmd {
      echoti cub 80
    }

I feel compelled to remark that moving 80 columns left seems an odd way of
achieving 'setopt promptcr'.

Re: $? being clobbered?

[Phil!Gregory]

* Bart Schaefer <schaefer@brasslantern.com> [2003-07-14 19:25 +0000]:
> There's code in the precmd handler to preserve and restore $? but nothing
> similar is done during prompt expansion.

I think my best approach is to move all program execution to precmd.

> Is there some reason to execute the command every time the prompt is
> printed?  That is, does the command change from one prompt to the next?

Yes, because it's actually $(echoti cub $COLUMNS) and I wish it to
work even when the terminal is resized.

> I feel compelled to remark that moving 80 columns left seems an odd way of
> achieving 'setopt promptcr'.

...which is even on by default.  The existing stuff is left over from my
old bash prompt; didn't realize zsh did it for me.  (Actually, the full
code did a clear-to-end-of-display, too, which zsh also appears to do by
default.)

I still have an invocation of apm while I'll have to move.

-- 
...computer contrarian of the first order... / http://aperiodic.net/phil/
PGP: 026A27F2  print: D200 5BDB FC4B B24A 9248  9F7A 4322 2D22 026A 27F2
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seem more afraid of life than death.
                       -- James F. Byrnes
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