Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:92516
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain gmail.com designates 209.85.213.196 as permitted sender)
MIME-Version: 1.0
Sender: jesseschalken@gmail.com
In-Reply-To: <CAESVnVqCZnrbHa+5_tSYG70VyvGfpZoDM98bEst3pg36HahYEg@mail.gmail.com>
References: <CADqTB_gUbfu91QRm1U0KyDjai8DKw7yCE6QxgUecy60oq3Zi8Q@mail.gmail.com>
	<CAKiSzdCO83XM0zqAeFnjQEMJvbd0yBmYAFnj0H6AtDumofVbkw@mail.gmail.com>
	<CAKiSzdCCEF=7OWtvZETG3bRoByCCLqEAEjuLW_H6m7MmDtJ8_g@mail.gmail.com>
	<CAFKaYMoQUUFLqgDjOHj3W0+a63u3s=vqnU5gWMCj0zvmvXFF5Q@mail.gmail.com>
	<3cc8a4c7-2640-11ae-a67b-06f909ac1e27@texthtml.net>
	<CAESVnVqCZnrbHa+5_tSYG70VyvGfpZoDM98bEst3pg36HahYEg@mail.gmail.com>
Date: Wed, 20 Apr 2016 12:56:27 +1000
Message-ID: <CAF1yvAQoBaT5zt1TRf_o8SRg3Ss-yqeujrOo7UcjqAccmLbfAA@mail.gmail.com>
To: Sara Golemon <pollita@php.net>
Cc: Mathieu Rochette <mathieu@texthtml.net>, Dominic Grostate <codekestrel@googlemail.com>, 
	Josh Di Fabio <joshdifabio@gmail.com>, PHP internals <internals@lists.php.net>, 
	"Ben Scholzen 'DASPRiD'" <mail@dasprids.de>, Rasmus Schultz <rasmus@mindplay.dk>
Content-Type: multipart/alternative; boundary=089e0158b3066fbe2e0530e1bd62
Subject: Re: [PHP-DEV] [RFC:generics]
From: me@jesseschalken.com (Jesse Schalken)

--089e0158b3066fbe2e0530e1bd62
Content-Type: text/plain; charset=UTF-8

On Wed, Apr 20, 2016 at 8:22 AM, Sara Golemon <pollita@php.net> wrote:

> On Tue, Apr 19, 2016 at 1:16 PM, Mathieu Rochette <mathieu@texthtml.net>
> wrote:
> > about the upper bounds, have you consider another way of describing the
> > constraints, eg:
> >
> > class Box<T> where T is Boxable
> >
> > this would allow multiple constraints, eg:
> >
> > class Collection<T> where T is Traversable, T is Countable
> >
> IMO, this sort of problem should be solved by combining this feature
> with union types, so you could have something like:
>
> class Collection<T as (Traversable | Countable)> {...
>
> And merely inherit the logic rules from that feature rather than
> inventing yet another one.
>
>
I think the "where T is Traversable, T is Countable" syntax was intended to
represent the intersection (i.e. a "Countable Traversable"), not the union.

So you would need an intersection syntax

class Collection<T as Traversable & Countable> {...




> > can generic types be nested ?
> >
> > class Stuff<A, B is Something<A, string>>
> >
> I can't imagine why not...
>
> For my part, I love the concept overall.  Generics are an important
> part of moving PHP towards comprehensive type-safety.  But then, you
> know how I feel about Hack. :)
>
> -Sara
>
> --
> PHP Internals - PHP Runtime Development Mailing List
> To unsubscribe, visit: http://www.php.net/unsub.php
>
>

--089e0158b3066fbe2e0530e1bd62--