Re: usort callback should always return integer (not float)

From: Date: Mon, 31 Mar 2014 10:54:50 +0000
Subject: Re: usort callback should always return integer (not float)
References: 1  Groups: php.internals 
Request: Send a blank email to [email protected] to get a copy of this message 
Am 31.03.2014 11:00, schrieb Nikita Nefedov:

Hi,

I've just stumbled upon this limitation in sorting (compare) callbacks. Is there any
reason why we can't handle floats in this case?

I think it would be nice to be able to return float from the callback
because it's often happens that all it does is just `return
$a->someMethod() - $b->someMethod();` (where someMethod() returns float) or `return $a["something"] -
$b["something"];` and to make it work I need to write additional if statement. I think the reasoning could be complex behavior of doubles? Especially comparing doubles. But will we see any double-related pitfalls when all our code does with it is `return retval < 0 ? -1 : retval > 0 ? 1 : 0;` (so essentially - compares them to zero)?


I made a PR [1] on github for 5.6 version. I think this change is pretty small and could go into 5.6 not breaking our release process rules? Though it WILL introduce some BC breaks for userland code that uses floats. But this code was already broken when it was relying on old behavior.

[1] https://github.com/php/php-src/pull/638



Hi,

try this:

<?php
$retval = 1.0 - 0.7 - 0.3;
var_dump($retval < 0 ? 'lt' : $retval > 0 ? 'gt' : 'equal'); // result is *not* equal

cryptocompress

Thread (5 messages)

« previous php.internals (#73487) next »