[swift-evolution] Introduce "associated_type" keyword

David Waite david at alkaline-solutions.com
Sat Dec 5 20:49:06 CST 2015


However, if a protocol wished to use type aliases not as part of a contract but for clarity, this would still need to be defined within the protocol in order for the associated types to be used in the typealias declarations.

-DW

> On Dec 5, 2015, at 7:29 PM, Dmitri Gribenko via swift-evolution <swift-evolution at swift.org> wrote:
> 
> On Sat, Dec 5, 2015 at 6:27 PM, Loïc Lecrenier <loiclecrenier at icloud.com> wrote:
>> Great :)
>> 
>> Also, this hasn't been explicitly discussed yet. But do you all agree about adding "real" typealias declarations (with the typealias keyword) inside protocols?
> 
> Concrete typealieases are not requirements, so they shouldn't be
> defined inside of a protocol.  Instead, they should be defined in the
> protocol extension.  In fact, this has been a plan of record for some
> time, but it wasn't implemented.
> 
> extension SequenceType {
>  typealias Element = Generator.Element
> }
> 
> Dmitri
> 
> -- 
> main(i,j){for(i=2;;i++){for(j=2;j<i;j++){if(!(i%j)){j=0;break;}}if
> (j){printf("%d\n",i);}}} /*Dmitri Gribenko <gribozavr at gmail.com>*/
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