From: Bart Schaefer <schaefer@brasslantern.com>
To: Bart Schaefer <schaefer@brasslantern.com>,
Zsh hackers list <zsh-workers@zsh.org>
Subject: Re: Up-scope named references, vs. ksh
Date: Fri, 1 Mar 2024 23:29:35 -0800 [thread overview]
Message-ID: <CAH+w=7aAHb5qc2ZmjgKPKw0vX4sFRpPhdKhYtfMuFGQK0L2qxA@mail.gmail.com> (raw)
In-Reply-To: <CAH+w=7YAgtUDrrgrDedVpq478ow7S=Renj+rjs0ZF6ZFTqP5OQ@mail.gmail.com>
On Wed, Feb 28, 2024 at 9:16 PM Bart Schaefer <schaefer@brasslantern.com> wrote:
>
> it's akin to attempting to allocate new space in your caller's stack
> frame in C (except there's one stack for each parameter name).
On Fri, Mar 1, 2024 at 12:34 PM Bart Schaefer <schaefer@brasslantern.com> wrote:
>
> zsh uses dynamic scoping, and ksh also has special handling of
> "typeset -n ref=$1" (and other positionals) that is simply never going
> to happen in zsh.
How about this: Instead of magically turning a positional into a
reference into the surrounding scope, let's make it explicit.
I propose that when the -u flag is combined with the -n flag, the
named reference refers to the enclosing scope, even if there's a local
of that name already in scope. Otherwise (without -u) normal dynamic
scoping applies. So in an example like this:
y () {
typeset $1=Y
typeset -nu upref=$1
upref=UP
echo In y:
typeset -p $1
}
z () {
local var
y var
echo In z:
typeset -p var
}
The output would be:
In y:
typeset var=Y
In z:
typeset var=UP
However, there's no good way around the stack problem, so removing the
declaration in z --
z () {
y var
echo In z:
typeset -p var
}
-- will cause an error at the "upref=UP" assignment in y. Or that
assignment could just silently fail, which already happens in a couple
of existing tests. The decision on that probably rests on what to do
with prefix assignments, e.g., if it's an error then
upref=UP /bin/echo bad
would print a message and not execute at all. If instead the
assignment does nothing but set $?, then /bin/echo will execute and
its status will determine $?.
next prev parent reply other threads:[~2024-03-02 7:30 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-06 2:21 [PATCH 1/3]: Add named references Bart Schaefer
2023-02-08 3:45 ` Oliver Kiddle
2023-02-08 4:59 ` Bart Schaefer
2023-02-08 23:16 ` Bart Schaefer
2023-02-09 0:47 ` Oliver Kiddle
2023-02-09 2:01 ` Oliver Kiddle
2023-02-09 5:45 ` Bart Schaefer
2023-02-09 4:49 ` Bart Schaefer
2023-02-09 20:49 ` Oliver Kiddle
2023-02-09 23:07 ` Bart Schaefer
2023-02-11 3:04 ` Bart Schaefer
2023-02-11 3:55 ` Bart Schaefer
2023-02-11 5:36 ` Speaking of dangerous referents Bart Schaefer
2023-02-12 8:00 ` Oliver Kiddle
2023-02-12 8:34 ` Bart Schaefer
2023-02-11 7:02 ` [PATCH 1/3]: Add named references Oliver Kiddle
2023-02-11 7:45 ` Bart Schaefer
2023-02-11 23:43 ` Bart Schaefer
2023-02-11 23:45 ` Bart Schaefer
2023-02-12 7:38 ` Oliver Kiddle
2024-02-11 7:00 ` Stephane Chazelas
2024-02-11 16:14 ` Bart Schaefer
2024-02-11 16:42 ` Bart Schaefer
2024-02-18 3:26 ` Up-scope named references, vs. ksh Bart Schaefer
2024-02-20 21:05 ` Stephane Chazelas
2024-02-20 22:30 ` Bart Schaefer
2024-02-21 20:12 ` Stephane Chazelas
2024-02-29 5:16 ` Bart Schaefer
2024-03-01 18:22 ` Stephane Chazelas
2024-03-01 20:34 ` Bart Schaefer
2024-03-02 7:29 ` Bart Schaefer [this message]
2024-03-02 23:55 ` [PATCH] "typeset -nu" (was Re: Up-scope named references, vs. ksh) Bart Schaefer
2024-03-01 23:28 ` Up-scope named references, vs. ksh Bart Schaefer
2024-03-03 13:44 ` Stephane Chazelas
2024-03-03 19:04 ` Bart Schaefer
2024-03-03 20:27 ` Stephane Chazelas
2024-03-03 22:58 ` Bart Schaefer
2024-03-04 19:59 ` Stephane Chazelas
2024-03-05 1:05 ` Oliver Kiddle
2024-03-05 2:53 ` Bart Schaefer
2024-03-05 5:43 ` Mikael Magnusson
2024-03-05 6:30 ` Stephane Chazelas
2024-03-06 5:04 ` [PATCH] local vs. nameref scoping (was Re: Up-scope named references, vs. ksh) Bart Schaefer
2023-02-12 9:02 ` [PATCH 1/3]: Add named references Oliver Kiddle
2023-02-12 18:59 ` Bart Schaefer
2023-02-12 19:45 ` PM_* flags in zsh.h (was Re: [PATCH 1/3]: Add named references) Bart Schaefer
2023-02-12 21:01 ` Oliver Kiddle
2023-02-12 22:54 ` [PATCH 1/3]: Add named references Oliver Kiddle
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