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From: Zoltan Hidvegi <hzoli@cs.elte.hu>
Message-Id: <199610162228.AAA00459@hzoli.ppp.cs.elte.hu>
Subject: Re: pushd
To: zefram@dcs.warwick.ac.uk (Zefram)
Date: Thu, 17 Oct 1996 00:28:22 +0200 (MET DST)
Cc: schaefer@nbn.com, zsh-workers@math.gatech.edu
In-Reply-To: <5016.199610161810@stone.dcs.warwick.ac.uk> from Zefram at "Oct 16, 96 07:10:53 pm"
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> Oh, what was the reasoning behind requiring "(UID=123; foo)" where
> "UID=123 foo" used to work?  I liked the exporting syntax.

It was the simplest way to handle special parameters.  If you say
parameter=value command the given environment variable is always set to
value even if it is a special parameter or integer or anything.  So now
UID=hzoli printenv UID says hzoli.  In case of UID it may net be the
desired behaviour but in some other cases this makes things simpler.  I
also liked the exporting syntax but I often tried to use that to a zsh
function or to a builtin which caused irreversibly lost privileges.
Offtopic but note that USERNAME is much more secure as it now executes
initgroups() as well similarily to su username (this is new, zsh-3.0.0 does
not do that).

A somewhat related question:

% ksh
$ readonly foo=foo    
$ foo=bar printenv foo
ksh: foo: is read only

% zsh
% readonly foo=foo    
% foo=bar printenv foo
bar

The current bash version behaves similarily but I talked to the bash
maintainer and he thinks that the ksh behaviour is the correct one and
bash-2.0 will now allow this.  Similar question:

% ksh
$ typeset -i i=12
$ i=foo printenv i
0

Zsh prints foo here.  That's why UID=798 command does not work.

Zoltan