Re: AW: [PHP-DEV] FILTER_VALIDATE_INT and +0/-0

On Mon, 04 Feb 2013 12:14:50 +0100, Frank Liepert <Frank.Liepert@gmx.de> wrote:

The change to FILTER_VALIDATE_INT seems to be inconsistent. First of all, take the following bug (https://bugs.php.net/bug.php?id=54096) where it says "PHP defines -0 as an int.". Where does PHP define it? The documentation says: "An integer is a number of the set ℤ = {..., -2, -1, 0, 1, 2, ...}." Secondly, try the following code: var_dump(round(-0.1)); What is the result? Surprise: float(-0) And it is not a bug (https://bugs.php.net/bug.php?id=42477) To sum it up: - FILTER_VALIDATE_INT should never treat "+0" or "-0" as valid integers. - Instead, var_dump needs to be corrected. - It could be even gone further in adding support for signed zero arithmetic (see IEEE754).

You're confusing things. Floats are irrelevant to this discussion. It's clear -0. (float) does exist and has a well defined meaning. The situation is manifestly different for integers because there are no separate positive and negative 0 integers in most likely all the architectures PHP runs on. So the question is only whether "+0" or "-0" (or "+0", etc.) should be accepted as integers by FILTER_VALIDATE_INT. I think they should, because we also accept non-canonical inputs such as "+5", i.e., we always accept a sign. It's true that 0 is neither positive or negative, but I don't think "accepts a leading sign, except if it's 0" is a good option. It's an unnecessary special case. Finally, please don't top post. See http://lxr.php.net/xref/PHP_TRUNK/README.MAILINGLIST_RULES#67 -- Gustavo Lopes