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
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