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To: "'Rasmus Schultz'" <rasmus@mindplay.dk>,
	"'PHP internals'" <internals@lists.php.net>
Cc: "'Ben Scholzen'" <mail@dasprids.de>,
	"'Dominic Grostate'" <codekestrel@googlemail.com>
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Date: Thu, 21 Apr 2016 19:26:41 +0200
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Subject: AW: [PHP-DEV] [RFC:generics]
From: php@tutteli.ch ("Robert Stoll")

Hi Rasmus

=20
> Hello internals,
>=20
> I'd like to introduce an RFC proposing the addition of generic types =
and functions:
>=20
> https://wiki.php.net/rfc/generics
>=20
> Ben Scholzen started this RFC as a quick draft with a few code samples =
in August last year, and I have since then worked
> with Dominic and Ben towards a more complete, detailed RFC.
>=20
> There are a few holes still, which is why it hasn't moved from Draft =
to Under Discussion yet, but we feel that it's complete
> enough that we can start a discussion about this feature and try to =
iron out the remaining details.
>=20
> The RFC was previously "unofficially" announced on reddit - this =
thread generated some good questions and may answer
> some of the most immediate questions:
>=20
> =
https://www.reddit.com/r/PHP/comments/3zx8qs/php_rfcgenerics_update_03_pl=
ease_comment/
>=20
> One of the most common criticisms we've heard, is that the syntax =
would be hard to implement, a few have said
> "impossible" - but we feel that, if generics are introduced, it's =
important that the syntax and features be as familiar as
> possible to developers who are experienced with other mainstream web =
industry languages, such as C# and Java.
>=20
> To that end, Dominic Grostate has worked through most of the =
tokenizer/parser issues - save for one very exotic edge
> case, his fork demonstrates that the proposed syntax can be parsed:
>=20
> https://github.com/orolyn/php-src/commits/generics
>=20
> Note that this fork is by no means an implementation of generics - it =
is proof of concept as far as being able to parse the
> syntax.
>=20
> We're hoping to find someone, with more experience working on the php =
codebase, who is willing to collaborate on
> further implementation - and we do also have a partial test-suite, =
defining the big picture expectations for most of the
> proposed language features:
>=20
> =
https://github.com/orolyn/php-src/tree/generics-tests/Zend/tests/generics=

>=20
> We look forward to your comments, questions and (I'm sure) criticisms =
of this proposal!
>=20
> Thank You,
>=20
> Regards,
>    Rasmus Schultz
>=20
> --
> PHP Internals - PHP Runtime Development Mailing List To unsubscribe, =
visit: http://www.php.net/unsub.php

Some questions about bounds checking:
- Example A: why don't you pass T (instead of Computer) to =
MachineBuilder? Just for the example or is it not possible with your =
approach?
- What about lower bounds?

In you examples about type checking you write:
> var_dump($hat_box instanceof Box); // =3D> (bool) true
Will you support "raw types" similar as in Java, if so why?

you wrote:
> TODO: decide whether or not bounded polymorphism should be supported.

I am a bit confused, isn't parametric polymorphism combined with upper =
bounds already bounded polymorphism?