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Date: Sat, 01 Jun 2024 05:13:49 +0000
To: Larry Garfield <larry@garfieldtech.com>
Cc: php internals <internals@lists.php.net>
Subject: Re: [PHP-DEV] [RFC] [discussion] Correctly name the rounding mode and make it an Enum
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From: internals@gpb.moe ("Gina P. Banyard")

On Friday, 31 May 2024 at 18:15, Larry Garfield <larry@garfieldtech.com> wr=
ote:

> On Fri, May 31, 2024, at 4:41 PM, Jorg Sowa wrote:
>=20
> > Hey Saki,
> > I like this change. When I was implementing additional rounding modes
> > for the next PHP version I was initially struggling with the naming and
> > this change will be helpful.
> >=20
> > I have only one concern about the names `NegativeInfinity` and
> > `PositiveInfinity`. They may be too formal from the user's perspective.
> > As we already have functions `ceil` and `floor` it's more intuitive for
> > developers to understand the logic of ceiling and floor rounding.
> >=20
> > But if voters will prefer those terms then it makes sense to change the
> > constants implemented in PHP 8.4 (and thus not released yet) from
> > `PHP_ROUND_(CEILING|FLOOR)` to
> > `PHP_ROUND_(POSITIVE_INFINITY|NEGATIVE_INFINITY)` for the sake of
> > consistency.
> >=20
> > Kind regards,
> > Jorg
>=20
>=20
> I was confused by those as well. It's not obvious to me what those even d=
o. Do they mean "away from 0"? If not, then I have no clue what they are. :=
-)
>=20
> --Larry Garfield

Considering that there are already "Away from 0" and "Towards 0" enum cases=
, the Towards Positive Infinity/Towards Negative Infinity cases "obviously"=
 don't mean this.

Towards positive infinity means that for positive numbers you round to the =
integer part plus 1, and for negative numbers you "just" take the negative =
integer part.
Similarly, for rounding towards negative infinity positive numbers round to=
 "just" the integer part of it, and negative numbers round to the negative =
integer part minus 1.

It should also be noted that ceil/floor is very English specific terminolog=
y that may not be immediately obvious to non-English speakers, thus my pref=
erence for using some variation of towards positive/negative infinity.


Best regards,

Gina P. Banyard