From: Sebastian Gniazdowski <sgniazdowski@gmail.com>
To: Zsh hackers list <zsh-workers@zsh.org>
Subject: Re: [PATCH] Support the mksh's ${|func;} substitution
Date: Tue, 10 Sep 2019 04:20:20 +0200 [thread overview]
Message-ID: <CAKc7PVCLpZ6_+bK8iQW0qPLB0t-iNcZmHV9WsWNGoCm_85QODA@mail.gmail.com> (raw)
In-Reply-To: <CAKc7PVB-V8Gqd2Pg8X=YjQDyPC=zG3keaKtdiS8cFCgfUOT_EA@mail.gmail.com>
I thought that I ask: should I continue working on the feature? I.e.
does it have a chance of being accepted?
The feature would be: a new substitution flag (x for execute, or | to
mark similarity to mksh's ${|code;}) that would execute the provided
code and substitute the value of $REPLY. E.g.:
- var='REPLY=test'; echo ${(x)var} -> test
- echo ${(x):-REPLY=test2} -> test2
- noglob print -rl ${(x):-for val (test test3) {
REPLY=\$val
}}
-> test3
The usefulness is the ability to map code onto array elements (with
(#m) or (#b) flags) and general lambda-like use-case.
On Sat, 7 Sep 2019 at 23:19, Sebastian Gniazdowski
<sgniazdowski@gmail.com> wrote:
>
> On Sat, 7 Sep 2019 at 22:19, Stephane Chazelas
> <stephane.chazelas@gmail.com> wrote:
> >
> > 2019-09-07 20:09:57 +0200, Sebastian Gniazdowski:
> > > The parsing would have to be changed to prevent the "=" in function names?
> > [...]
> >
> > No, I meant that you'd need the parser to handle that case of a
> > pseudo-command group (a {any shell code here} but with {|
> > instead of {)).
> >
> > So you can do:
> >
> > echo ${|
> > whatever $(...)
> > for i do
> > ...
> > done}
> >
> > Whether it would actually be difficult or not I can't comment,
> > I've not looked at the parser code.
>
> I think that it's already supported with the single exception that }
> would have to be quoted:
>
> % print ${|
> whatever $(...)
> for i do
> ...
> done;}
> zsh: no such function: \n whatever $(...)\n for i do\n ...\n done
>
> > Having an operator that *only* invokes a function to do an
> > expansion is less useful IMO. That just sound like a very
> > limited form of command substitution where you could have done a
> > more complete form by allowing any code instead of just one
> > function invocation without argument.
>
> Ok, I agree, the lambda-function reminiscent version is better. It
> also isn't much harder to implement – instead of the doshfunc() just
> bin_eval() would have to be called. I attach such patch. However, it
> has some problems:
>
> arr=( val1 val2 abc1 abc3 )
> print ${arr[@]//(#b)(*)/${|REPLY\=test;}}
> Output:test test test test
>
> So the = has to be quoted. Also, not much more works. REPLY\=$MATCH
> nor REPLY\=\$MATCH are working. I wonder why, as it doesn't look that
> bad in general:
>
> whatever() { echo func ran; }
> echo ${|
> whatever $(...)
> for i in a b c; do
> REPLY\=1
> done;}
>
> Output:
> func ran
> 1
>
> --
> Sebastian Gniazdowski
> News: https://twitter.com/ZdharmaI
> IRC: https://kiwiirc.com/client/chat.freenode.net:+6697/#zplugin
> Blog: http://zdharma.org
--
Sebastian Gniazdowski
News: https://twitter.com/ZdharmaI
IRC: https://kiwiirc.com/client/chat.freenode.net:+6697/#zplugin
Blog: http://zdharma.org
next prev parent reply other threads:[~2019-09-10 2:21 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-06 0:52 Sebastian Gniazdowski
2019-09-06 0:54 ` Sebastian Gniazdowski
2019-09-06 23:16 ` Sebastian Gniazdowski
2019-09-07 12:16 ` Daniel Shahaf
2019-09-07 15:07 ` Stephane Chazelas
2019-09-07 18:09 ` Sebastian Gniazdowski
2019-09-07 20:19 ` Stephane Chazelas
2019-09-07 21:19 ` Sebastian Gniazdowski
2019-09-10 2:20 ` Sebastian Gniazdowski [this message]
2019-09-10 5:29 ` Bart Schaefer
2019-09-10 18:21 ` Sebastian Gniazdowski
2019-09-10 19:38 ` Bart Schaefer
2019-09-12 0:08 ` Sebastian Gniazdowski
2019-09-12 1:03 ` Bart Schaefer
2019-09-12 2:06 ` Sebastian Gniazdowski
2019-09-12 5:35 ` Bart Schaefer
2019-09-12 6:00 ` Sebastian Gniazdowski
2019-09-12 6:55 ` Bart Schaefer
2019-09-13 20:28 ` Sebastian Gniazdowski
2019-09-13 21:33 ` Bart Schaefer
2019-09-13 21:36 ` Bart Schaefer
2019-09-14 0:41 ` Sebastian Gniazdowski
2019-09-14 0:44 ` Sebastian Gniazdowski
2023-05-03 14:46 Sebastian Gniazdowski
2023-07-04 1:55 ` Bart Schaefer
2023-07-04 18:53 ` Lawrence Velázquez
2023-07-05 5:32 ` Bart Schaefer
2023-07-05 6:30 ` Bart Schaefer
2023-07-06 1:39 ` Bart Schaefer
2023-07-06 2:27 ` Mikael Magnusson
2023-07-06 4:00 ` Bart Schaefer
2023-07-18 3:14 ` Bart Schaefer
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAKc7PVCLpZ6_+bK8iQW0qPLB0t-iNcZmHV9WsWNGoCm_85QODA@mail.gmail.com \
--to=sgniazdowski@gmail.com \
--cc=zsh-workers@zsh.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.vuxu.org/mirror/zsh/
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).