zsh-users
 help / color / mirror / code / Atom feed
From: Mikael Magnusson <mikachu@gmail.com>
To: Dmitri Vereshchagin <dmitri.vereshchagin@gmail.com>
Cc: Zsh Users <zsh-users@zsh.org>
Subject: Re: question about parameter expansion
Date: Sat, 26 Sep 2015 15:37:15 +0200	[thread overview]
Message-ID: <CAHYJk3QegiGeqwiw834TVW+tFzvW5+HKV0cvopDyxOJnrZ6LYQ@mail.gmail.com> (raw)
In-Reply-To: <20150926101839.GA14021@gmail.com>

On Sat, Sep 26, 2015 at 12:18 PM, Dmitri Vereshchagin
<dmitri.vereshchagin@gmail.com> wrote:
> Hello.
>
> Here is a code sample I would like to rewrite using parameter expansion
>
>   if (( ${+foo} )); then
>     bar=
>   else
>     bar=baz
>   fi
>
> Cannot find it in the docs, but I suppose there is a way to do that.  Am
> I right?
>
> Thanks.
>
> --
> Dmitri Vereshchagin

You have to think outside the box for this one,
bar=${${${+foo}#1}//0/baz}

-- 
Mikael Magnusson


  reply	other threads:[~2015-09-26 13:37 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-26 10:18 Dmitri Vereshchagin
2015-09-26 13:37 ` Mikael Magnusson [this message]
2015-09-26 17:41   ` ZyX
2015-09-26 17:57     ` Mikael Magnusson
2015-09-26 18:08   ` Dmitri Vereshchagin
2015-09-26 18:33     ` Mikael Magnusson
2015-09-26 18:57       ` Dmitri Vereshchagin
2015-09-26 21:11         ` Ray Andrews
2015-09-26 21:34           ` Bart Schaefer
2015-09-26 22:02             ` Ray Andrews
2015-09-27 16:58               ` Bart Schaefer
2015-09-27 18:29                 ` Ray Andrews
2015-09-27 18:43                   ` ZyX
2015-10-02 14:10                 ` Simon Ruderich
2015-10-02 16:35                   ` Ray Andrews
2015-10-02 19:07                     ` Simon Ruderich
2015-10-02 19:50                       ` Ray Andrews
2015-10-02 20:03                         ` latest manual Ray Andrews
2015-10-02 20:23                           ` Ray Andrews
2015-10-02 20:53                             ` Bart Schaefer
2015-10-02 21:55                               ` Ray Andrews
2015-10-03 18:49                                 ` Bart Schaefer
2015-10-03 10:01                               ` Simon Ruderich
2015-10-02 20:58                             ` Andrew Janke

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=CAHYJk3QegiGeqwiw834TVW+tFzvW5+HKV0cvopDyxOJnrZ6LYQ@mail.gmail.com \
    --to=mikachu@gmail.com \
    --cc=dmitri.vereshchagin@gmail.com \
    --cc=zsh-users@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).