foo=($bar) vs foo=("$bar[@]")

foo=($bar) vs foo=("$bar[@]")

[Roderick Schertler]

The NEWS file says

    foo=$bar no longer creates an array even if bar is an array.  Use
    foo=( $bar ) or even better, foo=( "$bar[@]" ) instead.

In what way is "$bar[@]" better than $bar?  The extra line noise is a
point in favor of the simpler form, what benefit outweighs it?

I hope it's not just that it makes ksh programmers feel at home!  Being
able to say just $bar is one of zsh's big advantages in array handling.

-- 
Roderick Schertler
roderick@gate.net

Re: foo=($bar) vs foo=("$bar[@]")

[Peter Stephenson]

Roderick Schertler wrote:
> The NEWS file says
> 
>     foo=$bar no longer creates an array even if bar is an array.  Use
>     foo=( $bar ) or even better, foo=( "$bar[@]" ) instead.
> 
> In what way is "$bar[@]" better than $bar?

I think the point is it works even if shwordsplit is set.

% setopt shwordsplit
% args() { echo $#; }
% bar=('one word' 'another word')
% args $bar
4                                    # i.e. 'one' 'word' 'another' 'word'
% args "$bar[@]"
2                                    # i.e. 'one word' 'another word'

It still doesn't quite make ksh users feel it home, it needs to be
"${bar[@]}" for that.  In fact, with ksharrays (or `emulate ksh')
turned on you need it in zsh too, so perhaps the NEWS file ought to
have that if it's trying to be all-inclusive.

-- 
Peter Stephenson <pws@ifh.de>       Tel: +49 33762 77366
WWW:  http://www.ifh.de/~pws/       Fax: +49 33762 77413
Deutsches Elektronen-Synchrotron --- Institut fuer Hochenergiephysik Zeuthen
DESY-IfH, 15735 Zeuthen, Germany.

Re: foo=($bar) vs foo=("$bar[@]")

[Zefram]

Roderick Schertler wrote:
>In what way is "$bar[@]" better than $bar?  The extra line noise is a
>point in favor of the simpler form, what benefit outweighs it?

"$bar[@]" works in all cases, but $bar will drop empty array elements:

% foo=(a '' b)
% bar1=($foo)
% bar2=("$foo[@]")
% echo $#foo $#bar1 $#bar2
3 2 3

Also $bar is at the mercy of several options, but in "$bar[@]"
everything is explicit.

-zefram

Re: foo=($bar) vs foo=("$bar[@]")

[Roderick Schertler]

On Wed, 29 Jan 1997 15:17:35 +0000 (GMT), Zefram <zefram@dcs.warwick.ac.uk> said:
>
> "$bar[@]" works in all cases, but $bar will drop empty array elements:

Ouch, I didn't know that!  I guess that shows how much zsh programming I
actually do.

-- 
Roderick Schertler
roderick@gate.net