From: Bart Schaefer <schaefer@brasslantern.com>
To: Zsh hackers list <zsh-workers@zsh.org>
Subject: Re: Up-scope named references, vs. ksh
Date: Sun, 3 Mar 2024 11:04:03 -0800 [thread overview]
Message-ID: <CAH+w=7ZZjS3QZeK8R8Zy_ACHeJsFj_YoKk22R3EG0NhXaQHjFA@mail.gmail.com> (raw)
In-Reply-To: <20240303134413.74c7trikf73g5kjy@chazelas.org>
On Sun, Mar 3, 2024 at 5:44 AM Stephane Chazelas <stephane@chazelas.org> wrote:
>
> If that one can be fixed then why can't the main one
Because the outer-scope parameter object already exists in "that one".
As I keep saying, the problem is with creating a new parameter at a
lower scope (counting 0 as the global scope) when a parameter of that
name already exists at the current (greater than 0) scope.
> typeset -n var=$1
> typeset value=$2
If the parameter is magically created "in advance" (at the point of
"typeset -n") then it only works for global scalars -- if you try to
create an array using "var" you run into baffling stuff like this:
assign:3: value: attempt to assign array value to non-array
I think it's much more consistent for dynamic scoping to apply at the
time $var is referenced or assigned.
The patch in workers/52650 allows something like this to work:
assign() {
typeset value=$2
typeset -nu var=$1 # ignore local $value
case ${(t)var} in
(*scalar*) var=$value;;
(*array*) var=( $value );;
(*) print -u2 cannot assign;;
esac
}
declare -a value
assign value x
If a function wants to be able to actually add things to its calling
scope without fear of name clashes, it has to use unique local names
(e.g., a namespace). But with dynamic scoping it remains the case
that you can't add a name to the global scope if any function in the
call chain has pre-empted that name -- named references don't change
this basic rule.
next prev parent reply other threads:[~2024-03-03 19:04 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
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 [this message]
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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