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Subject: Re: [PHP-DEV] [RFC] Default constructors
From: smalyshev@gmail.com (Stanislav Malyshev)

Hi!

> Does it *really* make sense for PHP? What if that parent class 'Animal'
> from your example introduces a constructor that accepts, say, both
> `$owner` and `$what` as mandatory arguments? `parent::__construct()`

Then you need to rewrite all descendant classes anyway, this would be
API change, not an API-preserving refactoring. Essentially, you take the
Animal class and replace it with entirely different class with different
requirements. You'll have to rewrite all the code that constructs Animal
objects. This obviously is not the scenario I'm talking about (and of
course nowhere near recommended practice for any maintainable code).

> call in a descendant will appear broken (unintentionally, I suppose),
> won't it? That'll work in Java just fine, though.

In Java, you can not do that - if your ctor requires 2 arguments, you'd
have to give it 2 arguments. If you still have the default ctor, that'd
be fine, and so it will be in PHP - but in PHP you can not have two ctor
functions, so in PHP you do things differently, we use optional
arguments instead of using two functions. The meaning is the same though
- if you're able to call new Foo(), you should be able to call
parent::__construct() (or super() in Java case) on Foo. Except in Java
it works and in PHP it doesn't. That's what I want to fix.