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Date: Thu, 28 Apr 2011 22:15:39 +0200
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To: Martin Scotta <martinscotta@gmail.com>
Cc: =?UTF-8?Q?Johannes_Schl=C3=BCter?= <johannes@schlueters.de>, 
	Ferenc Kovacs <info@tyrael.hu>, Stas Malyshev <smalyshev@sugarcrm.com>, 
	Felipe Pena <felipensp@gmail.com>, internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [RFC] Return type-hint
From: peter.e.lind@gmail.com (Peter Lind)

2011/4/28 Martin Scotta <martinscotta@gmail.com>:

* snip *

> IMHO I would not trust on any return value, as PHP did not ensure anythin=
g
> about them.
> Even more, I do not write code that depend on return values, I prefer to
> use input/output parameters,

I cannot help but wonder why PHP is your language of choice. I mean no
disrespect, but PHP does not have strict typing (for a reason) and
forcing it upon PHP seems strange to me. Seeing as a) you'll either
have to implement the return type hinting yourself in which case you'd
know anyway what the return value is or b) you'd have to have others
implement it in their libraries in which case you'd have to wait years
for any noticeable effect, the feature seems useful only in edge cases
(such as Hiphop, which I think one can question the mainstream
usefulness of, currently).

Personally, I read code if I'm not sure what a given function/method
will return - or just test. I actually thought unit tests took care of
issues like this. I don't think having a list of possible return
values would make things simpler than the good old "try it and see" -
which is one of the greatest assets of PHP.

> This is the safer way I've found to achieve the same behavior
>
> function no_return(ReturnStatus $returnStatus) {
> =C2=A0 doSomething();
>
> =C2=A0 if ( itWasOk() )
> =C2=A0 {
> =C2=A0 =C2=A0 =C2=A0 $returnStatus->setReturnValue( new Foo ); // return =
type hint
> =C2=A0 =C2=A0 =C2=A0 $returnStatus->success(); // return status
> =C2=A0 }
> =C2=A0 elseif ( isWasCritical() )
> =C2=A0 {
> =C2=A0 =C2=A0 =C2=A0 $returnStatus->setException( new RuntimeException );
> =C2=A0 =C2=A0 =C2=A0 $returnStatus->exception(); // return status
> =C2=A0 }
> =C2=A0 else
> =C2=A0 {
> =C2=A0 =C2=A0 =C2=A0 $returnStatus->fail(); // return status
> =C2=A0 }
> }
>
> Of course I don't write all functions like this.
> This is pattern I use when I need to ensure that the type returned is val=
id.

I just return what I need to from the function/method or throw an
exception. Indicating that you want to throw an exception instead of
actually throwing one seems ... overly polite, at best. As far as I
can tell, you'd have to check the ReturnStatus object anyway, so I
don't see how you're any safer (PHP has functions for checking null
values, false values, try/catch blocks and other things too). But
maybe we're dealing with very different development environments and I
just cannot see the usefulness of the suggested as it wouldn't make a
positive difference in mine.

Just a perspective from a typical webdev.
Regards
Peter

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