It would still cause confusion if you were only to conform to a single protocol (P in "class A : P" is a class or a protocol?). This can be solved in code but I don't think it is necessary.
L On 22 July 2016 at 14:08, Goffredo Marocchi via swift-evolution <[email protected]> wrote: > I think that the current approach marks a regression in declarative > expressiveness as the notion of extending a class over implementing a > protocol is blurred while the concepts are IMHO not the same (the latter is > about behaviour conformance not a is a relationship): > > Class/struct B : Class/struct A <Protocol1 & Protocol2> > > > would be a clear and concise way to express it that would not be confused > even at a quick glance. > > Sent from my iPhone > > On 22 Jul 2016, at 14:47, Charlie Monroe via swift-evolution > <[email protected]> wrote: > > I agree that this is an issue. Mostly nowadays when more and more classes in > Swift do not have a superclass - it simply looks weird: > > class MyClass: DataSource > > One doesn't know whether "DataSource" is a class, protocol, etc. > Nevertheless, I do not feel that :: is the answer. I really liked, how ObjC > did it (which isn't possible with the generics now - is it?), but what about > something like this? > > class BaseClass [SomeDelegate, OtherDelegate, ProtocolX] > class MyClass: BaseClass [SomeDelegate, OtherDelegate, ProtocolX] > extension MyClass [OtherProtocol] > > > On Jul 22, 2016, at 3:14 PM, Vladimir.S via swift-evolution > <[email protected]> wrote: > > > I remember that this was discussed, but can't find any decision regarding > this.. So, as a last chance, don't we want in Swift 3.0, as big source > breaking change, separate class inheritance and protocol conformance in > syntax? > > > Sorry if there was a decision about this suggestions. Please let know in > this case. > > > I.e. when I see the following I can't understand if the class inherits from > base class and conforms to protocols or just conforms to two protocols: > > > class MyClass : First, Second, Third { > > } > > > We don't have a rule to name protocols with 'Protocol'/other suffix/prefix, > or classes with 'T'/'C' prefix or something like this, so I believe to > improve the clarity of code we should separate in syntax inheritance and > conformance. > > > As I understand we should discuss changes in these areas: > > > 1. class inheritance : > > class Child: BaseClass > > > 2. class conformance : > > class Child: SomeProtocol1, SomeProtocol2 > > > 3. class inheritance + conformance : > > class Child: BaseClass, SomeProtocol1, SomeProtocol2 > > > 4. protocol conformance for structs: > > struct Struct: SomeProtocol1, SomeProtocol2 > > > 5. protocol inheritance: > > protocol Child: BaseProtocol1, BaseProtocol2 > > > > My suggestions: > > > I) separate inheritance with double colon : > > > 1. class inheritance : > > class Child:: BaseClass > > > 2. class conformance : > > class Child: SomeProtocol1, SomeProtocol2 > > > 3. class inheritance + conformance : > > class Child:: BaseClass : SomeProtocol1, SomeProtocol2 > > > 4. protocol conformance for structs: > > struct Struct: SomeProtocol1, SomeProtocol2 > > > 5. protocol inheritance: > > protocol Child:: BaseProtocol1, BaseProtocol2 > > > > II) in class definition use parenthesis to separate inheritance and > conformance : > > > 1. class inheritance : > > class Child: BaseClass > > > 2. class conformance : > > class Child: (SomeProtocol1, SomeProtocol2) > > > 3. class inheritance + conformance : > > class Child: BaseClass (SomeProtocol1, SomeProtocol2) > > > 4. protocol conformance for structs: > > struct Struct: SomeProtocol1, SomeProtocol2 > > or > > struct Struct: (SomeProtocol1, SomeProtocol2) > > should be discussed > > > 5. protocol inheritance: > > protocol Child: BaseProtocol1, BaseProtocol2 > > > > III) special word like 'conforms' > > > 1. class inheritance : > > class Child: BaseClass > > > 2. class conformance : > > class Child: conforms SomeProtocol1, SomeProtocol2 > > or > > class Child conforms SomeProtocol1, SomeProtocol2 > > > 3. class inheritance + conformance : > > class Child: BaseClass conforms SomeProtocol1, SomeProtocol2 > > > 4. protocol conformance for structs: > > struct Struct: conforms SomeProtocol1, SomeProtocol2 > > or > > struct Struct conforms SomeProtocol1, SomeProtocol2 > > > 5. protocol inheritance: > > protocol Child: BaseProtocol1, BaseProtocol2 > > > > Thoughts? > > _______________________________________________ > > swift-evolution mailing list > > [email protected] > > https://lists.swift.org/mailman/listinfo/swift-evolution > > > _______________________________________________ > swift-evolution mailing list > [email protected] > https://lists.swift.org/mailman/listinfo/swift-evolution > > > _______________________________________________ > swift-evolution mailing list > [email protected] > https://lists.swift.org/mailman/listinfo/swift-evolution > _______________________________________________ swift-evolution mailing list [email protected] https://lists.swift.org/mailman/listinfo/swift-evolution
