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Date: Fri, 13 Dec 2013 16:15:07 +0800
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To: Kris Craig <kris.craig@gmail.com>
Cc: Marc Bennewitz <php@marc-bennewitz.de>, PHP internals list <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [PROPOSAL] Alphanumeric decrement
From: tjerk.meesters@gmail.com (Tjerk Meesters)

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Hi,

On Fri, Dec 13, 2013 at 3:09 PM, Kris Craig <kris.craig@gmail.com> wrote:

> On Thu, Dec 12, 2013 at 9:58 PM, Marc Bennewitz <php@marc-bennewitz.de
> >wrote:
>
> > 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".
> >
>
> Why not just have "a" decrement to an empty string (i.e. "") and an empty
> string increment to "a"?


Imagine a scenario in which an empty posted value is assumed to be a number
and so ++$x is applied; instead of getting the expected "1" they now get
"a" which, after an (int) cast will become 0 .. surprise!

Then a decrement on an empty string could trigger
> a warning and remain empty.  That way, we won't have situations where
> decrementing from "a" and incrementing back would output a number.
>

Actually, the increment of "" is "1", which is still a string; the
increment of "1" is int(2), though.

That said, isn't it bad enough that php already has exceptions such as:
* ++$x is not always the same as $x += 1
* ++false remains false, but ++null becomes int(1)

If decrementing strings should work, I would request to also make ++false
=> true and --true => false

Lastly, if I could go back in time I would have created str_inc() and
str_dec() so that + has a unambiguous meaning :)


>
> --Kris
>



-- 
--
Tjerk

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