Re: [PATCH] nextup.3: minor improvements

[Vincent Lefevre]

On 2024-08-08 07:16:03 -0500, G. Branden Robinson wrote:
> At 2024-08-08T10:07:35+0200, Alejandro Colomar wrote:
> > Hmmm, I see.  Thanks!  I think "If x is ±0" is the clearest way to say
> > it.  I'm not sure if that glyph is available everywhere, though.  How
> > about "If x is 0 or -0"?
> 
> I think it's reasonable to assume that it's available.[1]  groff's
> terminal output devices will either output it as-is or substitute a
> fallback.
> 
> $ printf '±\n' | groff -K utf8 -T ascii | cat -s
> +-
> 
> An argument could be made that this fallback should render "+/-"
> instead.
> 
> With low-capability devices, there's often no single best answer to how
> one should limp along.

FYI, +-0 could be interpreted by the reader as in C, where a unary
minus operator is applied, then a unary plus operator. And about +/-0,
the "/" is already used a the division operator, so that this doesn't
help parsing.

So ideally, the fallback for "±0" should be "+0 or -0", which is
much more readable and less ambiguous than "+-0" or "+/-0". But
this would imply the following:

> In groff, of course, you can ask an output device whether it supports a
> given glyph and define a string appropriately--but the first part of
> that is not portable to formatters that don't implement groff
> extensions, and doing so could rouse the ire of Ingo Schwarze's
> mandoc(1).

Anyway, currently, for consistency, this should be "+0 or -0",
as this is already used:

cventin:~/software/man-pages> grep -r '\+0 or' man
man/man3/tgamma.3:Pole error: \fIx\fP is +0 or \-0
man/man3/tgamma.3:an argument of +0 or \-0 incorrectly produced a domain error
man/man3/pow.3:is +0 or \-0,
man/man3/pow.3:is +0 or \-0,
man/man3/atan2.3:is +0 or \-0, \-pi/2 is returned.
man/man3/atan2.3:is +0 or \-0, pi/2 is returned.
man/man3/cosh.3:is +0 or \-0, 1 is returned.
man/man3/erfc.3:is +0 or \-0, 1 is returned.

-- 
Vincent Lefèvre <vincent@vinc17.net> - Web: <https://www.vinc17.net/>
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