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Date: Wed, 20 Apr 2016 16:28:54 +0100
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Subject: Re: [PHP-DEV] [RFC:generics]
From: rowan.collins@gmail.com (Rowan Collins)

guilhermeblanco@gmail.com wrote on 20/04/2016 15:44:
> In a given class, I might want to only accept CacheDrivers that also
> support BulkOperations. How would I achieve that?

Apologies if this has been refuted elsewhere, but AFAIK you can 
implement any intersection constraint, albeit slightly more verbosely, 
by creating a new type:

- You can create a new interface that expresses an intersection of two 
other interfaces:

interface BulkOperationCacheDriver extends CacheDriver, BulkOperation {}

- Similarly, the intersection of a class and an interface can be created 
as an abstract class:

abstact class BulkRedisCacheDriver extends RedisCacheDriver implements 
BulkOperation {}

Since you can create those without modifying the underlying classes, you 
could specify generic constraints for any given intersection. A union 
constraint ("it can be either this or this") cannot currently be 
implemented, but the use cases are somewhat more questionable anyway.

Regards,
-- 
Rowan Collins
[IMSoP]