From: Luc Teirlinck <teirllm@dms.auburn.edu>
To: jay.p.belanger@gmail.com
Cc: jay.p.belanger@gmail.com, emacs-devel@gnu.org
Subject: Re: Calc: `*' binds more strongly than `/'
Date: Wed, 20 Jun 2007 14:28:45 -0500 (CDT) [thread overview]
Message-ID: <200706201928.l5KJSjA7025362@jane.dms.auburn.edu> (raw)
In-Reply-To: <87fy4mzf3z.fsf@gmail.com> (message from Jay Belanger on Wed, 20 Jun 2007 12:54:08 -0500)
Jay Belanger wrote:
I can't offhand; that's what I asked about.
It can never make any difference in an expression containing only *
and /.
Indeed, what happens with equal precedence and left associativity in
an expression without parentheses containing only * and / is that any
`* a' (`/ a'. resp.) anywhere in the expression results in the final
result being bigger by (smaller by, resp.) a factor of a. Giving /
higher precedence results in exactly the same.
Things do make a difference if a third "multiplicative type operator",
say mod, is involved. If you give / and * equal precedence, then you
can be consistent and give these other ones exactly the same
precedence, and use left associativity (this is exactly what most
mathematical software I know of does with `mod', _unless_ they
_require_, as many do, explicit parentheses do disambiguate and throw
an error if these parentheses are missing). But if you give / higher
precedence than *. then you have to decide which relative precedence
these other operators get. Of course, that same problem occurs just
as much if you give * higher precedence than /, as Calc did up to know
and still does by default now (unless I misunderstood).
I do not know what preference Calc gives to mod, relative to / and *,
for either value of `calc-multiplication-has-precedence'.
Sincerely,
Luc.
next prev parent reply other threads:[~2007-06-20 19:28 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-14 11:57 Calc: `*' binds more strongly than `/' Christian Schlauer
2007-04-14 15:09 ` Jay Belanger
2007-04-15 19:21 ` Chong Yidong
2007-04-15 20:05 ` Stefan Monnier
2007-04-17 12:47 ` Randal L. Schwartz
2007-04-17 18:03 ` Stefan Monnier
2007-04-18 8:44 ` Kim F. Storm
2007-04-18 19:27 ` Stefan Monnier
2007-04-18 20:02 ` Davis Herring
2007-04-18 20:16 ` David Kastrup
2007-04-18 21:43 ` Davis Herring
2007-04-19 16:10 ` Stefan Monnier
2007-04-20 11:13 ` Randal L. Schwartz
2007-04-20 13:40 ` Stefan Monnier
2007-04-20 14:07 ` Jay Belanger
2007-04-22 1:31 ` Miles Bader
2007-04-22 10:19 ` Christian Schlauer
2007-04-22 10:23 ` Christian Schlauer
2007-04-22 19:47 ` Jay Belanger
2007-04-23 10:46 ` Jason Rumney
2007-04-23 13:03 ` Kim F. Storm
2007-04-23 15:54 ` Jay Belanger
2007-04-25 19:56 ` Christian Schlauer
2007-04-25 20:54 ` Jay Belanger
2007-04-26 3:35 ` Stefan Monnier
2007-04-26 4:06 ` Jay Belanger
2007-04-26 14:11 ` Stefan Monnier
2007-04-26 21:07 ` Christian Schlauer
2007-04-26 15:07 ` Davis Herring
2007-04-26 16:01 ` Stefan Monnier
2007-04-26 18:32 ` Luc Teirlinck
2007-04-26 21:29 ` Christian Schlauer
2007-04-26 23:17 ` Luc Teirlinck
2007-04-26 21:07 ` Christian Schlauer
2007-04-27 1:27 ` Jay Belanger
2007-04-26 17:47 ` Davis Herring
2007-06-20 15:23 ` Jay Belanger
2007-06-20 16:02 ` Kim F. Storm
2007-06-20 17:13 ` Jay Belanger
2007-06-20 17:29 ` Luc Teirlinck
2007-06-20 17:54 ` Jay Belanger
2007-06-20 19:14 ` Kim F. Storm
2007-06-20 19:28 ` Luc Teirlinck [this message]
2007-06-20 20:18 ` Jay Belanger
2007-04-17 18:54 ` Jay Belanger
2007-04-18 21:55 ` Christian Schlauer
2007-04-19 2:58 ` Daniel Brockman
2007-04-22 10:27 ` Christian Schlauer
2007-04-26 16:00 ` Daniel Brockman
2007-04-19 15:16 ` Drew Adams
2007-04-19 17:05 ` David Kastrup
2007-04-19 17:18 ` Drew Adams
2007-04-19 17:33 ` David Kastrup
2007-04-16 15:38 ` Richard Stallman
2007-04-17 12:47 ` Randal L. Schwartz
2007-04-18 21:29 ` Christian Schlauer
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