From: "Richard Hartmann" <richih.mailinglist@gmail.com>
To: "Richard Hartmann" <richih.mailinglist@gmail.com>,
"Peter Stephenson" <p.w.stephenson@ntlworld.com>,
"Zsh hackers list" <zsh-workers@sunsite.dk>
Subject: Re: arithmetic operator precedence
Date: Tue, 17 Jun 2008 12:45:03 +0200 [thread overview]
Message-ID: <2d460de70806170345w2f6863f2u8c79504b0914333e@mail.gmail.com> (raw)
In-Reply-To: <20080617103829.GD5016@sc.homeunix.net>
On Tue, Jun 17, 2008 at 12:38, Stephane Chazelas
<Stephane_Chazelas@yahoo.fr> wrote:
> Not sure what you mean. ^ in bc is the power operator and
> there's no ** there. In shells, ** is the power operator and ^
> is the XOR operator.
I did not refer to the XOR interpretation of ^, of course.
What I thought you said is that ^ and ** as in
3^2 = 9
3**2 = 9
are not the same. Did not make sense to me, but did not want
to discard the idea entirely without checking.
> What I meant is that ^ reminds of the /human/ (as opposed to
> /computer/) representation as it indicates that follows must be
> raised up as in 3². So, one can understand that it should follow
> the same rules (that is -3^2 should be the same as -3², even
> though that's not what POSIX decided for bc). But given that **
> has more the shape of the * operator, I'm not sure we can tell
> the same thing.
I can see what you mean, but the operator, not its representation,
must be must stay the same. Do I understand you correctly that
you think this is the way to go:
-3^2 = -9
-3**2 = 9
If yes, that looks _really_ harmful to me.
> Anyway, I was just curious about Peter's statement. I'm most
> probably not as versed in maths as he is, so was curious about
> the rationale behind his statement about -3**2 = 9 not being
> mathematically correct.
See above for my question, requesting clarification.
Richard
next prev parent reply other threads:[~2008-06-17 10:45 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
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 [this message]
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
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