[swift-evolution] Operator implementation inside struct/class body

[Haravikk]

Definitely a +1 from me for the feature.

What are the name lookup issues? Do you mean cases where an operator for Foo == Foo exists in more than one location? Personally I’d just stick with what we have now, i.e- treat operator implementations within a specific class/struct as being globally defined anyway and throw an error if the same signature is declared more than once.

One minor issue around putting them in class/struct bodies though is that I wonder if perhaps a keyword other than func should be used? While they are functions, they aren’t methods of instances. At the very least they should probably need to be static.

> On 31 Jan 2016, at 05:26, Chris Lattner via swift-evolution <swift-evolution at swift.org> wrote:
> 
>> 
>> On Jan 30, 2016, at 9:03 PM, Vanderlei Martinelli via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
>> 
>> Since the first public betas I’d like to know why operator implementation have to be written outside the body of its owner.
> 
> Yep, this is a generally desirable feature (at least for symmetric operators).  This would also be great to get dynamic dispatch of operators within class declarations.  I don’t think we have a firm proposal nailing down how name lookup works with this though.
> 
> -Chris
> 
>> 
>> Take as example the code:
>> 
>> protocol MyEquatable {
>>     @warn_unused_result
>>     func ==(lhs: Self, rhs: Self) -> Bool
>> }
>> 
>> struct MyStruct: MyEquatable {
>>     let foo: String
>>     let bar: String
>> }
>> 
>> func ==(lhs: MyStruct, rhs: MyStruct) -> Bool {
>>     return lhs.foo == rhs.foo && lhs.bar == rhs.bar
>> }
>> 
>> Why we cannot write:
>> 
>> protocol MyEquatable {
>>     @warn_unused_result
>>     func ==(lhs: Self, rhs: Self) -> Bool
>> }
>> 
>> struct MyStruct: MyEquatable {
>>     let foo: String
>>     let bar: String
>>     
>>     func ==(lhs: MyStruct, rhs: MyStruct) -> Bool {
>>         return lhs.foo == rhs.foo && lhs.bar == rhs.bar
>>     }
>> 
>> }
>> 
>> Any thoughts?
>> 
>> 
>> -Van
>> 
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> 
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