From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <zsh-workers-request@math.gatech.edu>
Received: (qmail 26506 invoked from network); 12 Jan 1998 11:02:43 -0000
Received: from math.gatech.edu (list@130.207.146.50)
  by ns1.primenet.com.au with SMTP; 12 Jan 1998 11:02:43 -0000
Received: (from list@localhost)
	by math.gatech.edu (8.8.5/8.8.5) id FAA15116;
	Mon, 12 Jan 1998 05:45:05 -0500 (EST)
Resent-Date: Mon, 12 Jan 1998 05:43:43 -0500 (EST)
From: Andrew Main <zefram@tao.co.uk>
Message-Id: <199801121045.KAA05850@taos.demon.co.uk>
Subject: Re: Exporting arrays
To: adam.spiers@new.ox.ac.uk
Date: Mon, 12 Jan 1998 10:45:06 +0000 (GMT)
Cc: zsh-users@math.gatech.edu
In-Reply-To: <19980111181603.60292@thelonious.new.ox.ac.uk> from "Adam Spiers" at Jan 11, 98 06:16:03 pm
X-Loop: zefram@tao.co.uk
X-Headers: in preparation
X-Mailer: ELM [version 2.4 PL25]
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Resent-Message-ID: <"GpLq52.0.eh3.UFVkq"@math>
Resent-From: zsh-users@math.gatech.edu
X-Mailing-List: <zsh-users@math.gatech.edu> archive/latest/1219
X-Loop: zsh-users@math.gatech.edu
X-Loop: zsh-workers@math.gatech.edu
Precedence: list
Resent-Sender: zsh-workers-request@math.gatech.edu

Adam Spiers wrote:
>% foo=(a b c)
>% typeset | grep zzz
>array foo=(a b c)
>% export foo=(a b c)
>% typeset | grep zzz 
>array exported foo=(a b c)
>
>However,
>
>% unset foo
>% export foo=(a b c)
>% typeset | grep zzz 
>exported foo='(a b c)'

This sort of thing has cropped up before, and it has always been due to
human error.  </hal>

In the case of "export foo=(a b c)", the parens do not actually delimit
an array.  They are treated as globbing metacharacters.  This command runs
the builtin "export", with argument "foo=(a b c)", which it interprets as
a request to export the variable "foo" and set its value to the scalar
"(a b c)".  In the second of your dialogues, that's precisely what
happens.  In the first dialogue, you first set foo to be an array,
and the export command refused to change it to a scalar.

Btw, it's impossible to export an array.  Unix environment variables are
only strings.  There are ways an array could be encoded as a string,
but some other shells get very unhappy about apparently malformed
environment entries.

-zefram