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Date: Wed, 18 Sep 2013 09:50:30 -0400
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References: <CAPwsocGni4kjJq9c5wr77ohPU+YX2=0O7EgahdH=p0=hH1H_fA@mail.gmail.com> <49D57F66323040FC9AE48244DAAF3771@gmail.com>
To: Leigh <leight@gmail.com>
X-Mailer: Apple Mail (2.1503)
Subject: Re: [PHP-DEV] Re: Allowing is_* functions to accept multiple parameters
From: sean@seancoates.com (Sean Coates)

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> i.e. is_null($a, $b, $c) would be the same as is_null($a) && =
is_null($b)
> && is_null($c)

Note that this would not be semantically equivalent in this form, even =
if `is_null()` did accept multiple parameters, because of the =
short-circuiting with `&&`:

<?php

function are_null() {
	foreach (func_get_args() as $a) {
		if ($a !=3D=3D null) {
			return false;
		}
	}
	return true;
}

function destroy_data() { echo "DESTROYING DATA\n"; }

// old form: short-circuited; data is not destroyed
if (is_null(null) && is_null(false) && is_null(destroy_data())) {
	echo "All null.\n";
} else {
	echo "Not null.\n";
}

echo "----\n";

// proposed form: no short-circuit; parameters are evaluated at call =
time and data is destroyed
if (are_null(null, false, destroy_data())) {
	echo "Still null.\n";
} else {
	echo "Still not null.\n";
}


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