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Date: Thu, 22 Dec 2011 20:53:24 -0500
Cc: Stas Malyshev <smalyshev@sugarcrm.com>,
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To: =?iso-8859-1?Q?=C1ngel_Gonz=E1lez?= <keisial@gmail.com>
Subject: Re: [PHP-DEV] Return Type Hinting for Methods RFC
From: will.fitch@gmail.com (Will Fitch)


On Dec 22, 2011, at 7:33 PM, =C1ngel Gonz=E1lez wrote:

> On 23/12/11 01:00, Will Fitch wrote:
>> On Dec 22, 2011, at 6:28 PM, Stas Malyshev <smalyshev@sugarcrm.com> =
wrote:
>>> In PHP, returning object if everything is OK and false if not is a =
very common pattern.
>>> Also, you understand that always allowing null means that this =
construct:
>>>=20
>>> $foo =3D $this->returnsFoo();
>>> $foo->fooMethod();
>>>=20
>>> is no longer safe as you wanted it to be when you made returnsFoo =
use strict typing? You'd have to check $foo anyway.
>> Are you suggesting not allowing null to be returned, or provide an
>> indicator within the syntax that it may return null?=20
> It should be possible to allow it. Either with a generic syntax for
> allowing
> many types of return types or through a specific one (eg. in C# a ?
> marks an internal type as nullable: int? )

You can return null from methods.  Parameters and variables are =
nullable.  I'm not against appending an indicator as to whether null may =
be returned, but that would need to be a general consensus, I think.

I would like other opinions on this...

>=20
>> PHP would be the
>> first language I'm aware of that would do so in either case.
> It already barfs at you if you pass null to a parameter expecting a
> given class
> (though you can allow it).
>=20
>=20
>> The point isn't to restrict a type hint to always be returned. The
>> goal is to guarantee that if a value is returned, it will be of type
>> X. In the event it is inappropriate to return the value back, would
>> you rather receive null or a bogus class instance, empty array or a
>> random function name back? Because that's what will happen. It will
>> become the "workaround" for not being able to return null.
> As it would support both ways, it's up to the framework to choose if
> they want to
> return null or a fake-class interface.

Yes, it would.  But providing the option of null would be a good =
incentive not to do that.  At the end of the day, you're giving a set of =
tools to someone.  If they choose to use it in a way that's less =
efficient, or wrong in other's eyes, that's their choice.

>=20
>=20