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Possible bug in `expt'. (was: calc: E command hangs Emacs.)
From: |
Michaël Cadilhac |
Subject: |
Possible bug in `expt'. (was: calc: E command hangs Emacs.) |
Date: |
Fri, 21 Sep 2007 13:49:20 +0200 |
User-agent: |
Gnus/5.110007 (No Gnus v0.7) Emacs/23.0.50 (gnu/linux) |
"Robert J. Chassell" <address@hidden> writes:
> Please don't confuse us even when the original title is wrong!
> As a first sentence in the body of your message please write
>
> The following is Emacs Lisp, not Emacs Calc mode even though the
> title talks about Emacs Calc mode
Well, you know, the `References' field of my previous message is here if
you need context. The body of the text was all you needed, and it was
just pointing out a bug in the (expt) function, but sorry for the
misleading subject.
> In the body of your message, you attributed the Emacs Lisp to Yu Jie,
> which I think is correct:
Why, not quite. Yu Jie is quoted with `>', not `>>'.
> "yu jie" <address@hidden> writes:
>
> >> (let ((x -1))
> >> (while (condition-case nil
> >> (message "1.Expt is %e" (expt 10.0 x))
> >> (error nil))
> >> (message "1.`x' is now %d" (setq x (* 2 x))))
> >> (message "2.`x' is now %d" (setq x (/ x 2)))
> >> (while (condition-case nil
> >> (message "3.Expt is %e" (expt 10.0 x))
> >> (error nil))
> >> (message "3.`x' is now %d" (setq x (1- x))))
> >> (+ x 2))
That expression leads to a weird behavior on Yu's computer. In fact, it
never gets out the first loop, and `x' reaches 0 without any error.
> That expression is for Emacs Lisp, not Emacs Calc.
> In Emacs Calc mode, E computes the exponential, i.e., `e' raised to the
> power of a number you have given it.
And this function uses (expt), which is buggy.
Hope everybody understands the matter now.
--
| Michaël `Micha' Cadilhac | 21 seems like a good value: half of |
| http://michael.cadilhac.name | of 42 and just old enough to drink! |
| JID/MSN: | Why would you want to change it? |
`---- address@hidden | -- Stefan Monnier - --'
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- Re: calc: E command hangs Emacs., Michaël Cadilhac, 2007/09/21
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- Possible bug in `expt'. (was: calc: E command hangs Emacs.),
Michaël Cadilhac <=
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