Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:70616
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: error (pb1.pair.com: domain marc-bennewitz.de from 80.237.132.171 cause and error)
Message-ID: <52AAA1EA.7030106@marc-bennewitz.de>
Date: Fri, 13 Dec 2013 06:58:02 +0100
User-Agent: Mozilla/5.0 (X11; Linux i686; rv:24.0) Gecko/20100101 Thunderbird/24.2.0
MIME-Version: 1.0
To: internals@lists.php.net
References: <52AA1649.2090601@ajf.me>
In-Reply-To: <52AA1649.2090601@ajf.me>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Subject: Re: [PHP-DEV] [PROPOSAL] Alphanumeric decrement
From: php@marc-bennewitz.de (Marc Bennewitz)

Hi

Decrementing "a" to a number isn't a good idea because on incrementing
again you will increment the number and not go back to "a".

In my opinion this should be a warning/error and the value should stay
as "a".

This warning/error should be triggered on incrementing/decrementing a
non alphanumeric string (inclusive an empty string), too.

Greetings
Marc

Am 12.12.2013 21:02, schrieb Andrea Faulds:
> Good evening,
> 
> At present, it's possible to increment (++) an alphanumeric string, such
> that "a" when incremented becomes "b", "z" becomes "aa", and so on.
> 
> However, it's irritated me that the same is not true for the decrement
> (--) operator. At present, "aa" when decremented stays as "aa", and "b"
> when decremented stays as "b". This lack of symettry is counterintuitive
> to me. I don't think it's what you would expect here.
> 
> So I've written a patch which would change this. "aa" when decremented
> would be "z", and "b" when decremented would be "a". It also handles
> decrementing "a", which becomes "0". This creates an interesting new
> asymettry: {$a = "a"; $a--; $a++;} will result in $a being integer 1. I
> think it's better than the previous behaviour, though, which resulted in
> "b".
> 
> The diff is here:
> https://github.com/TazeTSchnitzel/php-src/compare/php:PHP-5.6...AlphanumericDecrement
> 
> 
> My aim is to try and get this into PHP 5.6, if people are interested.
> Thoughts?
>