From: Stephane Chazelas <Stephane_Chazelas@yahoo.fr>
To: Richard Hartmann <richih.mailinglist@gmail.com>
Cc: Peter Stephenson <p.w.stephenson@ntlworld.com>,
Zsh hackers list <zsh-workers@sunsite.dk>
Subject: Re: arithmetic operator precedence
Date: Tue, 17 Jun 2008 10:45:09 +0100 [thread overview]
Message-ID: <20080617094509.GC5016@sc.homeunix.net> (raw)
In-Reply-To: <2d460de70806170219k12ff4cadn441b52c48bf8076f@mail.gmail.com>
On Tue, Jun 17, 2008 at 11:19:40AM +0200, Richard Hartmann wrote:
[...]
> > That's an interesting point for C_PRECEDENCES since I was trying to get
> > it behave as much as possible like Perl. What does anyone else think?
>
> Being unsure myself, I did some somewhat extensive research. The only
> mathematically correct way of doing this is
>
> -3**2 = -9
> (-3)**2 = 9
[...]
In which way is it more "mathematically" correct?
Is that because -3² is -9?
But ** is not ^, it's a binary operator whose shape reminds that
of multiply, like a multiply++. And even then, POSIX's ^ in bc
is handled as -3^2 = 9.
It could be a good idea to ask ksh, POSIX/bc and perl authors for
the rationale behind their choices.
--
Stéphane
next prev parent reply other threads:[~2008-06-17 9:45 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-12 9:57 Stephane Chazelas
2008-06-12 13:12 ` Mikael Magnusson
2008-06-12 13:40 ` Peter Stephenson
2008-06-12 14:47 ` Bart Schaefer
2008-06-12 15:01 ` Stephane Chazelas
2008-06-16 8:17 ` Vincent Lefevre
2008-06-16 8:07 ` Vincent Lefevre
2008-06-16 13:42 ` Peter Stephenson
2008-06-16 13:59 ` Stephane Chazelas
2008-06-16 14:33 ` Vincent Lefevre
2008-06-17 9:19 ` Richard Hartmann
2008-06-17 9:45 ` Stephane Chazelas [this message]
2008-06-17 10:24 ` Richard Hartmann
2008-06-17 10:24 ` Richard Hartmann
2008-06-17 10:38 ` Stephane Chazelas
2008-06-17 10:43 ` Peter Stephenson
2008-06-17 11:28 ` Vincent Lefevre
2008-06-17 11:46 ` Peter Stephenson
2008-06-17 12:05 ` Vincent Lefevre
2008-06-19 9:37 ` Jun T.
2008-06-19 9:54 ` Stephane Chazelas
2008-06-19 16:00 ` Vincent Lefevre
2008-06-19 16:20 ` Stephane Chazelas
2008-06-19 17:14 ` Vincent Lefevre
2008-06-19 9:58 ` Peter Stephenson
2008-06-19 12:29 ` Richard Hartmann
2008-06-19 16:04 ` Vincent Lefevre
2008-06-19 16:10 ` Mikael Magnusson
2008-06-19 16:27 ` Stephane Chazelas
2008-06-19 17:25 ` Vincent Lefevre
2008-06-19 17:20 ` Vincent Lefevre
2008-06-17 10:45 ` Richard Hartmann
2008-06-17 11:38 ` Vincent Lefevre
2008-06-17 11:19 ` Vincent Lefevre
2008-06-17 11:57 ` Stephane Chazelas
2008-06-17 12:35 ` Vincent Lefevre
2008-06-17 12:46 ` Stephane Chazelas
2008-06-17 13:02 ` Vincent Lefevre
2008-06-17 13:20 ` Stephane Chazelas
2008-06-17 14:33 ` Vincent Lefevre
2008-06-17 14:53 ` Stephane Chazelas
2008-06-17 15:49 ` Vincent Lefevre
2008-06-17 14:35 ` Stephane Chazelas
2008-06-17 15:05 ` Vincent Lefevre
2008-06-17 10:54 ` Vincent Lefevre
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=20080617094509.GC5016@sc.homeunix.net \
--to=stephane_chazelas@yahoo.fr \
--cc=p.w.stephenson@ntlworld.com \
--cc=richih.mailinglist@gmail.com \
--cc=zsh-workers@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).