I'm surprised no one is raising a strong argument about the
"parent::__construct()" call, so I'll do it.
I never liked typing "parent::__construct()" to call parent's class
constructor, but now that this proposal is being discussed (and might even
be accepted) I would like to throw some more meat to the fire:
<?php
class C {
function __construct($a) {
print "C::__construct() a=$a\n";
}
}
class D extends C {
function __construct($a, $b) {
parent::__construct($a, $b); // how it is now
// parent($a); // how i would like it
print "D::__construct() a=$a b=$b\n";
}
}
$d = new D(10, 20);
If you go for blocking explicit calls to __construct() (i'm personally in
favour of it), i hope you would change the syntax for its only legitimate
use which is calling the parent's constructor within a constructor, so how
about something like parent(...)?
It would be ugly to say "You are not supposed to explicit call
__construct() *ever*" and then "You know what, to initialize parent class
you need to call __construct()".
The construct method is called automagically when you instantiate the
class, I don't type something like $d = new D; $d->__construct(10, 20); so
I don't see why I should type that method name inside my derived
constructor. I just need a special syntax to do so.
And while I'm at it (a bit offtopic but related to my previous argument)
how about *not* requiring __construct() to be defined in the parent class?
I.e. when you call parent::__construct() if there is NO constructor defined
in the parent class just do nothing instead of going fatal error. I
*always* wanted this feature, because when you do "new C;" it doesn't go
fatal error if there is no __construct() defined. I don't think this is
breaking covariance if you assume that every class defines an empty
__construct() with no argument. I mean, if you later add an explicit
constructor to the parent class it *must* be without arguments unless you
accept you might break something.
Thanks!
On 14 January 2017 at 13:15, Andreas Heigl <andr...@heigl.org> wrote:
>
>
> > Am 14.01.2017 um 11:26 schrieb Fleshgrinder <p...@fleshgrinder.com>:
> >
> >> On 1/14/2017 11:20 AM, Andreas Heigl wrote:
> >> Do we as "makers of PHP" want to dictate the user what the "intended"
> >> behaviour of PHP is? Or are we treating the user as a responsible person
> >> that knows what to do and also not to do?
> >>
> >> Personally I'm in favour of the later. Let the user be able to call
> >> __construct whenever they like. It's a special method which is clearly
> >> visible by the two underscores at the start. So the users either know
> >> exactly what they are doing or they need to learn it.
> >>
> >> Translated to a different example this discussion is like: "Let's remove
> >> the handle from the window because someone might be able to open the
> >> window and jump out of it". The handle is there for a valid reason. And
> >> as a window-maker I have no idea in what way it might be used. But I
> >> have to accept that there are people missusing it. But should I limit
> >> all those users with a valid use-case for it just to save some from
> >> missusing it? And if we start with that, where should we stop?
> >>
> >> Just my 0.02€
> >>
> >> Cheers
> >>
> >> Andreas
> >>
> >
> > Yes, that is exactly the question. This needs to be voted on. Rust would
> > be an example that protects you and C/C++ would be examples that do not.
> > Both approaches are valid approaches.
> >
> > Note that the dictation will not always work, this is why e.g. Rust has
> > unsafe blocks. The corresponding thing in PHP imho would be reflection.
> > Hence, if someone has a special case:
> >
> > - Rust: use unsafe
> > - PHP: use reflection
> >
> > --
> > Richard "Fleshgrinder" Fussenegger
>
> IMHO it already IS safe.
>
> In PHP 4 the "constructor" was a method thad had the same name as the
> class. But now it is a class that has always the same name and is always
> preceded with two underscores. There is no way to "accidentaly" call that
> method. You have to explicitly call "__construct" to "break" things.
>
> If developers "want" to break something they will find a way. Protecting
> "__construct" will not stop them from doing so. But it will stop the rest
> of us do legitimate things.
>
> Cheers
>
> Andreas
>
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--
Giovanni Giacobbi
