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bug#47302: 27.1; calc math-format-number formatting for floats without d
From: |
Dave Gillespie |
Subject: |
bug#47302: 27.1; calc math-format-number formatting for floats without decimals is unusual |
Date: |
Mon, 26 Apr 2021 14:58:12 +0000 |
Yes, that patch makes sense. Thanks, and thanks for helping with this old
beast!
-- Dave
-----Original Message-----
From: Mattias Engdegård <mattiase@acm.org>
Sent: Sunday, April 25, 2021 8:54 AM
To: Dave Gillespie <Daveg@synaptics.com>
Cc: Jelle Licht <jlicht@fsfe.org>; Stefan Kangas <stefan@marxist.se>;
47302@debbugs.gnu.org
Subject: Re: bug#47302: 27.1; calc math-format-number formatting for floats
without decimals is unusual
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22 apr. 2021 kl. 18.35 skrev Dave Gillespie <Daveg@synaptics.com>:
> Wow, it has been a long time since I got any correspondence on Calc!
Good to hear from you, Dave! I just fix the occasional Calc bug now and then.
> Calc has a C language mode ('d C' keystroke, controlled by calc-language).
> It is a good point that C mode (and probably others like it) should format
> integer-valued floats as "123.0" even if the default mode does not. If we
> apply Jelle's patch, I suggest making it conditional on calc-language so that
> it applies only in modes such as C mode. Or perhaps rework it as a text
> transformation using calc-language-filter.
>
> You could even create a JSON language mode, but most likely the basic C mode
> is close enough to serve that purpose.
These are all good suggestions. Most languages permit trailing decimal points;
the only common exceptions that I can think of are Haskell, Ada and Swift.
Apparently JSON is also one. Tying the float-format display to the C, Pascal
(etc) modes seems a bit incongruous as it has nothing to do with the syntax of
those languages.
How to display a floating-point number with zero fraction also depends on what
the user wants to do with the result, so there is a good argument for letting
him or her do the required post-processing. Sometimes '1.' should become '1.0',
sometimes '1'. For instance, in a LaTeX document it would depend on how the
author wants to represent significant digits. A JSON parser (such as the one in
Emacs) will parse '1.0' and '1' differently, as a float or integer respectively.
I wrote the patch below as a possible solution but in the light of the above,
perhaps it's not ideal?