I’ve taken some time to digest the current feedback and I’ve changed my mind.
The syntax for adding constraints to a sub-protocol in the protocol’s
definition where clause is starting to grow on me. Before I modify the
proposal, I'd still like to understand something:
What is the use of declaring a default associated types with the `=` syntax in
protocols? I’ve never used them and I don’t understand what they provide.
> On 26 Apr 2016, at 15:53, Douglas Gregor <dgre...@apple.com> wrote:
>
>
>
> Sent from my iPhone
>
> On Apr 25, 2016, at 10:03 PM, Brent Royal-Gordon <br...@architechies.com>
> wrote:
>
>>> Note that, if we do the above, I’d love to make it an error to define a new
>>> associated type with the same name as an associated type in an inherited
>>> protocol. It’s odd that we do so, and IIRC the only use case for it is to
>>> add requirement to an “existing” associated type.
>>
>> You also do it to specify or change a default associated type. This is from
>> an older copy of the stdlib source code, but I believe there's still
>> something equivalent:
>>
>> public protocol CollectionType : Indexable, SequenceType {
>> associatedtype Generator: GeneratorType = IndexingGenerator<Self>
>
> Ah yes, of course! Thank you.
>
> - Doug
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