Re: [RFC][Draft] Body-less __construct

On Tue, May 11, 2021 at 6:56 PM Matt Fonda <matthewfonda@gmail.com> wrote: > On Tue, May 11, 2021 at 7:45 AM Nikita Popov <nikita.ppv@gmail.com> wrote: > >> My thought here is that a constructor with (only) promoted properties is >> hardly a constructor at all -- it's more like a special syntax for >> declaring properties that happens to re-use the constructor notation, >> because that allows it generalize in certain ways. It could have been >> implemented with some other syntax that didn't explicitly mention >> constructors at all, such as class Point($x, $y, $z) {} or something. >> > > Agreed. I've personally been a little hesitant to start using CPP because > of this. Declare constructor parameters AND declare properties AND > magically provide a constructor implementation that sets their values. It > looks like a constructor, but it's actually a little different. For me, > this proposal would really help clear that up. > > When I see a method with an empty body, I think "this method does have an > implementation, and that implementation does exactly nothing." In the case > of CPP, this isn't true. The method appears to do exactly nothing, but in > fact it has an automatically defined implementation that sets the > properties to the given values. > > When I see a semi-colon-terminated method, I think "this method has no > implementation *here*; one will be provided from somewhere else." This is > the case in abstract classes and interfaces--the subclass provides the > implementation. And it's the case in CPP too--an implementation that sets > the properties to the given values is automatically provided. For this > reason, I don't see it as inconsistent. The semi-colon means someone else > will provide an implementation, and CPP does just that. > After you put it into these terms, this reminds me a lot of https://wiki.php.net/rfc/property_accessors#implicit_implementation. For accessors there's very much a difference between public $prop { get; } // auto-generated get and public $prop { get {} } // explicit get that doesn't do anything Making "allow replacing {} with ;" as a general feature would certainly pose a problem for this choice of syntax (which is inspired by C#). Regards, Nikita