From: Phil Pennock <zsh-workers+phil.pennock@spodhuis.org>
To: Bart Schaefer <schaefer@brasslantern.com>
Cc: zsh-workers@zsh.org
Subject: Re: Is this a bug? Why not?
Date: Tue, 30 Mar 2010 23:06:02 -0700 [thread overview]
Message-ID: <20100331060602.GA91691@redoubt.spodhuis.org> (raw)
In-Reply-To: <100330224612.ZM1818@torch.brasslantern.com>
On 2010-03-30 at 22:46 -0700, Bart Schaefer wrote:
> macadamia% print $ZSH_VERSION $ZSH_PATCHLEVEL
> 4.3.10-dev-1 1.4947
> macadamia% print ${var-???}
> CVS Doc Etc Src
> macadamia% print ${${var}-???}
>
> macadamia% print ${${var}+???}
> CVS Doc Etc Src
> macadamia% print ${${var}:-???}
> CVS Doc Etc Src
> macadamia% print ${${var}:+???}
>
> macadamia%
So the string ${var} when treated as a variable-name is empty but
defined? The four expansions with a nested ${var} are entirely
consistent with the behaviour when expanding a variable which is defined
with a value of length 0.
Seems unusual, but consistent.
In bash, ksh, bad substitution. In ksh93, it gets weird:
$ echo ${var-???}
OSM SCM bin dbg doc etc lib man src tmp www
$ echo ${${var}-???}
ksh93: syntax error: `!' unexpected
The ksh reference-name expansion made me think of the somewhat opposite
expansion in zsh, (P)var ...
Hrm, zsh 4.3.10 1.4705:
% print ${(P)-???}
zsh: 0239BCJPXZgiklms: ??
% print ${(P)+???}
zsh: bad substitution
% print ${(P):-???}
OSM SCM bin dbg doc etc lib man src tmp www
% print ${(P):+???}
%
Strange that the first entry is somehow tying into expanding $- for the
shell options ...
% print ${-}
0239BCJPXZgiklms
% print ${(P)-}
% print ${(P)-?}
zsh: 0239BCJPXZgiklms: parameter not set
That strikes me as dubious. You?
next prev parent reply other threads:[~2010-03-31 6:06 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-31 5:46 Bart Schaefer
2010-03-31 6:06 ` Phil Pennock [this message]
2010-03-31 15:11 ` Bart Schaefer
2010-04-01 8:26 ` Phil Pennock
2010-04-01 14:36 ` Bart Schaefer
2010-04-01 21:57 ` Phil Pennock
2010-04-01 22:51 ` Bart Schaefer
2010-04-09 14:37 ` Peter Stephenson
2010-04-17 13:06 ` Mikael Magnusson
2010-04-18 19:11 ` Peter Stephenson
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