From: Peter Stephenson <pws@csr.com>
To: zsh-users@sunsite.dk
Subject: Re: Case statement with ";|" [not implemented]
Date: Fri, 19 Jan 2007 12:01:20 +0000 [thread overview]
Message-ID: <200701191201.l0JC1KkO003663@news01.csr.com> (raw)
In-Reply-To: <070118205243.ZM30783@torch.brasslantern.com>
Bart Schaefer wrote:
> } Note that ";|" provides an OR-like separator (as opposed to the AND-like
> } ";&" separator)
>
> This analogy doesn't work. Semantically, the test for whether $mycase
> matches any one of the labels occurs once at the top of the statement.
> Control then jumps into the body as if with a GOTO, and thereafter all
> you're able to change with ;& is how early you exit from the body. It
> isn't anything like AND / OR.
>
> By comparison, your proposed ;| requires the interpreter to reproduce
> the pattern match test at every label, which implies storing the result
> of expanding $mycase, etc. Most languages don't allow one to hide quite
> that much complexity behind syntactic sugar.
I think we simply have to apply the restriction that the word in the
case statement is expanded only once at the start of the case statement.
I don't see that's either unnatural or confusing. With this it looks
like it ought to be quite straightforward, possible even trivial, to
implement.
--
Peter Stephenson <pws@csr.com> Software Engineer
CSR PLC, Churchill House, Cambridge Business Park, Cowley Road
Cambridge, CB4 0WZ, UK Tel: +44 (0)1223 692070
To access the latest news from CSR copy this link into a web browser: http://www.csr.com/email_sig.php
To get further information regarding CSR, please visit our Investor Relations page at http://ir.csr.com/csr/about/overview
prev parent reply other threads:[~2007-01-19 12:02 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-18 19:53 Gerald Lai
2007-01-19 4:52 ` Bart Schaefer
2007-01-19 12:01 ` Peter Stephenson [this message]
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=200701191201.l0JC1KkO003663@news01.csr.com \
--to=pws@csr.com \
--cc=zsh-users@sunsite.dk \
/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).