From: Emanuel Berg via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org>
To: help-gnu-emacs@gnu.org
Subject: Re: What is 0.01 here not 0.01 here 0.009999999999999?
Date: Fri, 16 Apr 2021 22:41:30 +0200 [thread overview]
Message-ID: <87o8eehshx.fsf@zoho.eu> (raw)
In-Reply-To: courier.0000000060671F59.00003B9F@stw1.rcdrun.com
Jean Louis wrote:
> I would like to get a number increased for 0.01:
>
> (defun rcd-vc-increase-decimal-revision-number (nn.nn)
> (let* ((nn.nn (format "%s" nn.nn))
> (nn.nn (format "%.2f" (string-to-number nn.nn)))
> (nn.nn (string-to-number nn.nn)))
> (+ nn.nn 0.01)))
>
> But result is not what I want, as I want to get 10.13,
> though it is tiny loss:
>
> (rcd-vc-increase-decimal-revision-number "10.12") ; 10.129999999999999
Indeed, good question...
It is a binary thing, how floats are implemented.
Conventional wisdom is, it doesn't matter, don't worry
about it.
In your case, if you want a version number that is
MAJOR.MINOR.PATCH what you can do is have them integer
integer integer and then a separate function to output them
(format "%d.%d.%d" major minor patch)
I prefer to use the time of change for versions, but that's
just me - and what a horrible world it would be, if everyone
was the same - and for larger/join projects it should/could
be extended, but still, check out:
https://dataswamp.org/~incal/emacs-init/time-insert.el
--
underground experts united
https://dataswamp.org/~incal
next prev parent reply other threads:[~2021-04-16 20:41 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-02 13:42 What is 0.01 here not 0.01 here 0.009999999999999? Jean Louis
2021-04-02 13:56 ` Stefan Monnier
2021-04-02 17:03 ` Jean Louis
2021-04-02 17:41 ` Teemu Likonen
2021-04-02 18:44 ` Jean Louis
2021-04-02 20:46 ` John Yates
2021-04-02 21:19 ` Jean Louis
2021-04-02 22:04 ` John Yates
2021-04-02 23:29 ` Jean Louis
2021-04-03 4:39 ` Arthur Miller
2021-04-03 5:36 ` Jean Louis
2021-04-03 3:56 ` Arthur Miller
2021-04-03 5:19 ` Jean Louis
2021-04-03 13:54 ` Stefan Monnier
2021-04-02 14:02 ` Eli Zaretskii
2021-04-02 17:07 ` Jean Louis
2021-04-03 4:49 ` Arthur Miller
2021-04-16 20:41 ` Emanuel Berg via Users list for the GNU Emacs text editor [this message]
2021-04-17 10:53 ` Jean Louis
2021-04-19 10:51 ` Eric S Fraga
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