比方说我有:
- struct S {
- var num = 0
- }
我想实现一个函数allEqual()作为Array< S>的扩展,所以我可以这样做
- var s1 = S()
- var s2 = S()
- var s3 = S()
- var equality = [s1,s2,s3].allEqual()
比如说具体的类型是S.
- extension CollectionType where Generator.Element == S {
- }