GNU bug report logs -
#914
In CVS Emacs, calc-eval gives multiplication higher precedence than division
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Reported by: Francis Litterio <flitterio <at> gmail.com>
Date: Sun, 7 Sep 2008 16:20:03 UTC
Severity: normal
Merged with 915,
918,
920,
921,
923,
924,
928,
929,
930,
932,
933,
934,
937,
941,
944
Done: Chong Yidong <cyd <at> stupidchicken.com>
Bug is archived. No further changes may be made.
Full log
Message #16 received at 914 <at> emacsbugs.donarmstrong.com (full text, mbox):
Randal L. Schwartz wrote:
>>>>>> "Lennart" == Lennart Borgman (gmail) <lennart.borgman <at> gmail.com> writes:
>
> Lennart> Of course I can see that the behaviour you want saves you a lot of key
> Lennart> strokes. My question is really about the default value. You can easily
> Lennart> change that, of course. The question is really if you prefer the old
> Lennart> default and in that case what arguments you want to present for that.
>
> There's no need to change the longstanding defaults, because it would break
> things. You already have a knob you can tweak if you think that "2 a / 3 b"
> should multiply by b, rather than divide by it. That's a personal choice.
I think communication can be very difficult if you have too much
personal choice in it. Math is about communication (for a special class
of logical problems).
The original bug report was about this
(calc-eval "1 / 2 * 1000")
Calc treats this as 1 / (2 * 1000) which is just plain wrong. I have
never seen a mathematician treat it that way - though I have seen many
pupils doing that.
> Frankly, I'd never touch that knob, because it looks to me like it should
> divide by b. And I think most mathemeticians would agree, and that's the
> target for that part of Calc. Stop thinking computer science. Think
> *math* notation.
This bug report was last modified 16 years and 282 days ago.
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