Re: Return Type Hinting for Methods RFC

On Dec 22, 2011, at 7:33 PM, Ángel González 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: >>> >>> $foo = $this->returnsFoo(); >>> $foo->fooMethod(); >>> >>> 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? > 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... > >> 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). > > >> 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. > >