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Message-ID: <57179C5F.9090101@garfieldtech.com>
Date: Wed, 20 Apr 2016 10:12:31 -0500
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Subject: Re: [PHP-DEV] [RFC:generics]
From: larry@garfieldtech.com (Larry Garfield)

On 4/20/16 10:01 AM, Rowan Collins wrote:
> guilhermeblanco@gmail.com wrote on 20/04/2016 03:54:
>> 1- Even though mentioned, I'd still use "extends" or "implements" 
>> instead
>> of "is" (which would be a new pseudo-reserved keyword) to enforce 
>> data type
>> consistency and prevent developers to potentially referring to one thing
>> while consider another.
>
> Perhaps "instanceof" would make more sense here? "class 
> FileProcessor<T extends FileHandle>" seems to exclude instantiating 
> FileProcessor<FileHandle>, because "FileHandle extends FileHandle" 
> doesn't make any sense.
>
> You could read "class Box<T instanceof Boxable>" as an assertion that 
> the class passes the constraint, as in "public function __construct(T 
> $t) { assert($t instanceof Boxable); }"
>
> Regards,

I'm not an expert in generics by any means, but how is that different 
than just

public function __construct(Boxable $t) {}

I thought the point of generics was for cases like "these two variables 
must be the same type, but they can be any same type."

-- 
--Larry Garfield