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Date: Thu, 4 Sep 2008 07:39:34 -0400
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Subject: RE: [PHP-DEV] [RFC] [PATCH] Rounding in PHP
From: jbondc@openmv.com ("Jonathan Bond-Caron")

On Thu Aug 28 01:47 PM, Christian Seiler wrote:
> Hi again,
>=20
>> A few weeks ago I wrote quite a long posting to internals@ that tried =

>> to clarify the situation on the round() function in PHP. I was asked=20
>> to write it up as an RFC in the wiki, which I have done:
>>=20
>> http://wiki.php.net/rfc/rounding
>=20
> Since there has been no reaction so far to my proposal (besides the=20
> help from Hannes and Pierre for the Win32 build dependencies, thanks=20
> for that btw.), I'd like to know why? Am I talking gibberish and my=20
> proposal is hard to understand? Or have I simply chosen a topic that=20
> many do not consider worthwhile investing that amount of energy into?
> Or is it something else?

For the record, I was very excited to see your proposal and the work =
you've done.=20

I'm not a PHP dev so I can't comment on the patch, maybe there might be =
a performance concern?
I don't know either the history of the 'rounding fuzz', but there's =
definitely space for improvement... The problem naturally isn't with =
floats but that the round() function is very misleading. My opinion is =
the rounding precision should be removed or fixed since it doesn't work =
"as expected". i.e. javascript, there's no precision: Math.round()

"
Nevertheless, what could be discussed separately is the introduction of =
a new type that automatically uses an arbitrary precision library =
internally, since writing $a * $b is much more natural than e.g. =
bcmul($a, $b). This, however, goes far beyond the scope of this =
proposal.
"

I'm all for this... maybe something like this:

// within some 'numeric' precision
$a =3D (numeric)2;
$b =3D (numeric)0.5;
$mult =3D $a * $b;
echo $mult;// 1 (numeric)

echo (2.5 =3D=3D $a + $b); // true=20
echo (2.5 =3D=3D=3D $a + $b); // false
echo ((numeric)2.5 =3D=3D=3D $a + $b); // true