From: Stephane Chazelas <stephane@chazelas.org>
To: Bart Schaefer <schaefer@brasslantern.com>
Cc: Peter Stephenson <p.w.stephenson@ntlworld.com>,
Zsh hackers list <zsh-workers@zsh.org>
Subject: Re: [PATCH (not final)] (take three?) unset "array[$anything]"
Date: Mon, 14 Jun 2021 08:19:40 +0100 [thread overview]
Message-ID: <20210614071940.xugzcv63habfegjo@chazelas.org> (raw)
In-Reply-To: <CAH+w=7YKqdJJvLjF3-oEiwc2pQqosUZLcJz0OC7-KqCA7_e11Q@mail.gmail.com>
2021-06-13 14:44:03 -0700, Bart Schaefer:
> On Sun, Jun 13, 2021 at 12:50 PM Peter Stephenson
> <p.w.stephenson@ntlworld.com> wrote:
> >
> > Yes, in fact those are the same thoughts that flitted through my mind.
>
> One other idea ... NO_UNSET could warn if you unset something that's
> not set, as well as when you $deref something that's not set. That
> would at least blat at you if your hash key was misinterpreted.
Note that nounset is a POSIX option. And for the unset special
utility:
"Unsetting a variable or function that was not previously set
shall not be considered an error and does not cause the shell to
abort."
POSIX has no jurisdiction over arrays/hashes, but that does mean
we can't have unset fail on unset variables when in sh emulation
at least.
A shell that would fail upon:
unset var
When var was not previously set would not be compliant.
A script that would do
unset "var[foo]"
Would not be a POSIX script as var[foo] is not a valid variable
name, so implementations are free to do whatever they want for
them. But if zsh returned failure for when var[foo] is not set
and not in unset var, that would make it quite inconsistent.
Changing the behaviour would likely break some scripts that use
errexit as well.
--
Stephane
next prev parent reply other threads:[~2021-06-14 7:20 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-16 21:10 regexp-replace and ^, word boundary or look-behind operators Stephane Chazelas
2019-12-16 21:27 ` Stephane Chazelas
2019-12-17 7:38 ` Stephane Chazelas
2019-12-17 11:11 ` [PATCH] " Stephane Chazelas
2019-12-18 0:22 ` Daniel Shahaf
2019-12-18 8:31 ` Stephane Chazelas
2020-01-01 14:03 ` [PATCH v2] " Stephane Chazelas
2021-04-30 6:11 ` Stephane Chazelas
2021-04-30 23:13 ` Bart Schaefer
2021-05-05 11:45 ` [PATCH v3] regexp-replace and ^, word boundary or look-behind operators (and more) Stephane Chazelas
2021-05-31 0:58 ` Lawrence Velázquez
2021-05-31 18:18 ` Bart Schaefer
2021-05-31 21:37 ` [PATCH] (?) typeset array[position=index]=value Bart Schaefer
2021-06-01 5:32 ` Stephane Chazelas
2021-06-01 16:05 ` Bart Schaefer
2021-06-02 2:51 ` [PATCH] (take two?) typeset array[position=index]=value / unset hash[$stuff] Bart Schaefer
2021-06-02 10:06 ` Stephane Chazelas
2021-06-02 14:52 ` Bart Schaefer
2021-06-02 16:02 ` Stephane Chazelas
2021-06-02 9:11 ` [PATCH] (?) typeset array[position=index]=value Stephane Chazelas
2021-06-02 13:34 ` Daniel Shahaf
2021-06-02 14:20 ` Stephane Chazelas
2021-06-02 15:59 ` Bart Schaefer
2021-06-03 2:04 ` [PATCH (not final)] (take three?) unset "array[$anything]" Bart Schaefer
2021-06-03 2:42 ` Bart Schaefer
2021-06-03 6:12 ` Bart Schaefer
2021-06-03 8:54 ` Peter Stephenson
2021-06-03 13:13 ` Stephane Chazelas
2021-06-03 14:41 ` Peter Stephenson
2021-06-04 19:25 ` Bart Schaefer
2021-06-05 18:18 ` Peter Stephenson
2021-06-09 23:31 ` Bart Schaefer
2021-06-13 16:51 ` Peter Stephenson
2021-06-13 18:04 ` Bart Schaefer
2021-06-13 19:48 ` Peter Stephenson
2021-06-13 21:44 ` Bart Schaefer
2021-06-14 7:19 ` Stephane Chazelas [this message]
2021-06-03 18:12 ` Bart Schaefer
2021-06-04 8:02 ` Stephane Chazelas
2021-06-04 18:36 ` Bart Schaefer
2021-06-04 20:21 ` Stephane Chazelas
2021-06-05 0:20 ` Bart Schaefer
2021-06-05 17:05 ` Stephane Chazelas
2021-06-10 0:14 ` Square brackets in command position Bart Schaefer
2021-06-03 6:05 ` [PATCH (not final)] (take three?) unset "array[$anything]" Stephane Chazelas
2021-06-03 6:43 ` Bart Schaefer
2021-06-03 7:31 ` Stephane Chazelas
2021-06-10 0:21 ` [PATCH] (?) typeset array[position=index]=value Bart Schaefer
2021-06-05 4:29 ` Mikael Magnusson
2021-06-05 5:49 ` Bart Schaefer
2021-06-05 11:06 ` Mikael Magnusson
2021-06-05 16:22 ` Bart Schaefer
2021-06-18 10:53 ` Mikael Magnusson
2024-03-08 15:30 ` [PATCH v3] regexp-replace and ^, word boundary or look-behind operators (and more) Stephane Chazelas
2024-03-09 8:41 ` [PATCH v5] " Stephane Chazelas
2024-03-09 9:21 ` MBEGIN when =~ finds bytes inside characters (Was: [PATCH v5] regexp-replace and ^, word boundary or look-behind operators (and more).) Stephane Chazelas
2024-03-09 13:03 ` [PATCH v3] regexp-replace and ^, word boundary or look-behind operators (and more) Stephane Chazelas
2024-03-10 19:52 ` [PATCH v6] " Stephane Chazelas
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