Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:97066
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: error (pb1.pair.com: domain garfieldtech.com from 66.111.4.29 cause and error)
To: internals@lists.php.net
References: <CAHE1EdvM514MOvTRGU-CV2+hSAvtaOP+Q=xTH1z99EkyoZb+9w@mail.gmail.com>
 <CAFMT4NpZzbtJAC2eRgXwNrSP=-HFdGO_GOkgyGhBFLkLAReK1Q@mail.gmail.com>
 <CAKiSzdB5d9DCEVbx0ifbKo_QuX+zWZq+bPR2ARfw2HXpV1Jn8g@mail.gmail.com>
 <CAHE1Edu0C0ek6eq1RFRqXfiNwezD_Nr-ADvwdPC53P5VEa5b_w@mail.gmail.com>
 <CAKiSzdCm0yu10SQu4bgh4G5yX5CDnpThzdpaZH_zH+idM+V9Dg@mail.gmail.com>
 <b2c818cf-7978-61d3-c947-4881f705621b@gmail.com>
 <CANUQDChUZiQAyUi1BKeBeDdsVqNVk666p4V-V18w=-R0hj8scw@mail.gmail.com>
Message-ID: <839cc149-cfb3-c164-7aa0-d29845f538b7@garfieldtech.com>
Date: Sat, 19 Nov 2016 13:18:33 -0500
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101
 Thunderbird/45.4.0
MIME-Version: 1.0
In-Reply-To: <CANUQDChUZiQAyUi1BKeBeDdsVqNVk666p4V-V18w=-R0hj8scw@mail.gmail.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Subject: Re: [PHP-DEV] Countable Type Hint
From: larry@garfieldtech.com (Larry Garfield)

On 11/17/2016 10:12 AM, Niklas Keller wrote:
>> No, what Craig is proposing is a type hint that covers both the existing
>> Countable interface and primitives which are naturally countable.
>>
>> If the union types RFC had passed, you'd be able to say "array|Traversable
>> $foo"; a recent RFC lets you instead say "iterable $foo". The suggestion is
>> to add a keyword which similarly acts as "array|Countable $foo".
>>
>> Unfortunately, as others have pointed out, it can't be called just
>> "countable", because that's the name of the existing interface. The
>> principle seems sound though, assuming we don't want to go down the route
>> of treating arrays as implementing interfaces.
>>
> I think it's better to implement method calls on primitives than
> introducing new type keywords for every edge-case now. Once we have methods
> on primitives (counting array here as primitive), arrays can just implement
> the Countable interface and we're fine using Countable (the interface).
>
> Methods on primitives have the additional advantage that we can clean up
> the API and have improved readability when chaining e.g. array methods like
> filter and map.
>
> Regards, Niklas


Methods on primitives has been proposed a few times, but never gone 
anywhere because it's, well, really hard to do. :-)  Have you a 
recommendation for how to do so?

(Honest question; I'd love primitive methods, especially if they're 
user-extensible.)

--Larry Garfield