Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:25319
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Message-ID: <018701c6bd4f$28163d50$0201a8c0@pc1>
To: <internals@lists.php.net>, "Jochem Maas" <jochem@iamjochem.com>
References: <005101c6b930$83f30b30$0201a8c0@pc1>	<00fa01c6bd37$d61d1940$0201a8c0@pc1> <20060811141931.2ef39365@pierre-u64> <44DC84C0.7040807@iamjochem.com>
Date: Fri, 11 Aug 2006 09:05:09 -0500
MIME-Version: 1.0
Content-Type: text/plain;
	charset="UTF-8"
Content-Transfer-Encoding: 7bit
Subject: Re: [Simplistic End User View] Re: [PHP-DEV] is_numeric_string causes function inconsistency
From: php_lists@realplain.com ("Matt W")

Hi Jochem,

Leading whitespace is already allowed with PHP's is_numeric() function (and
corresponding internal one), math operations, etc.  Only when it precedes
.123 or -.123 does the behavior change. :-)


Matt


----- Original Message -----
From: "Jochem Maas"
Sent: Friday, August 11, 2006


Pierre wrote:
>> is_numeric(' .123') // bool(false)
>
> this one should return true.

as Pierre mentions further down changing this behaviour could cause pots of
problems for existing code. from an enduser POV having is_numeric(' .123')
return true (and therefore having maths operations using ' .123' use that
string
as if it was '.123' would be tantamount to doing:

$v = " .123";
$v = trim($v);
var_dump(is_numeric($v), ($v + 0));

In order to be able to move forward and allow for leading spaces in numeric
strings
maybe an ini setting could be used, one that defaults to false:

trim_numeric_strings_before_usage = 0;

such a setting if true would essentially trim space (like the trim()
function does)
form strings before they were checked (by is_numeric) and before being used
in
calculations.

in php6 the default of this ini setting could be changed to true (which
would
offer quite some time to check for possible unforeseen problems and
eventually
in php7,8,9 the setting could dissappear entirely once the community is
satisfied
any/all problems have been dissipated.

I have no idea if this is feasable or desirable (I'm aware of the animosity
towards
new ini settings!) but it might offer a potential resolution between moving
forward
and protecting muppets like myself from 'strange behaviour' related to
autocasting of
numeric strings.

rgds,
Joche,