[swift-evolution] [Pitch] separate syntax of class inheritance and protocol conformance

[Leonardo Pessoa]

I don't see this as a problem with the language but in how you're read
code, thus it's problem that could be solved on the IDE.

L


On 22 July 2016 at 13:13, Vladimir.S <svabox at gmail.com> wrote:
>> Perhaps a change to Xcode so it could colour differently classes and
>> protocols could be more benefic with no impact to the language. That
>> would solve the problem.
>
> IMO no enhancement in *IDE* could solve the problem of *language*.
> Swift code will be written/viewed not only in XCode and even not only in
> IDE.
>
>
> On 22.07.2016 18:56, Leonardo Pessoa wrote:
>>
>> I don't see this as an issue and I'm sure not comfortable in being
>> more verbose here or complicating the language unnecessarily. This is
>> not a change that will bring either benefit or consistency as there
>> are no other cases to compare the use of colon but these and variable
>> declarations (which also use only one).
>>
>> Perhaps a change to Xcode so it could colour differently classes and
>> protocols could be more benefic with no impact to the language. That
>> would solve the problem.
>>
>> L
>>
>> On 22 July 2016 at 12:13, Karl via swift-evolution
>> <swift-evolution at swift.org> wrote:
>>>
>>> What about if we defined subclasses with the “subclass” keyword instead
>>> of “class”? So you knew the first parameter was always going to be a base
>>> class?
>>>
>>> That way we keep the single “:” everywhere else - where clauses, generic
>>> constraints lists, etc.
>>>
>>>> On 22 Jul 2016, at 15:14, Vladimir.S via swift-evolution
>>>> <swift-evolution at swift.org> 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?
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>>>> swift-evolution at swift.org
>>>> https://lists.swift.org/mailman/listinfo/swift-evolution
>>>
>>>
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>>
>>
>