> On Nov 10, 2017, at 4:12 PM, Charles Srstka <cocoa...@charlessoft.com> wrote:
>
>> On Nov 10, 2017, at 5:51 PM, Joe Groff <jgr...@apple.com> wrote:
>>
>>
>>
>>> On Nov 10, 2017, at 3:45 PM, Charles Srstka <cocoa...@charlessoft.com>
>>> wrote:
>>>
>>>> On Nov 10, 2017, at 5:36 PM, Joe Groff <jgr...@apple.com> wrote:
>>>>
>>>> How `MyObject.foo(_:bar:)` gets implemented is its own business, as far as
>>>> the compiler is concerned. The compile-time name resolution for the method
>>>> isn't impacted.
>>>>
>>>> -Joe
>>>
>>> The compile-time name resolution for the method doesn’t happen *at all.*
>>
>> You declared the method in your @interface, and the compiler saw that and
>> brought it in as what Swift considers to be a regular method, and your call
>> on the Swift side was resolved to it by Swift's usual lookup rules. To do
>> what Chris is suggesting requires changing the way calls get resolved in the
>> compiler before the call is even formed.
>
> The only thing that makes this the “usual lookup rules” is that the
> Objective-C bridge has already been implemented.
As I mentioned in my original reply, I personally think the "importer" approach
would be superior, and that in a perfect world we'd have type providers to make
writing something like the ObjC importer but for a different language or other
dynamic data source something that doesn't require invasive compiler hackery.
The importer puts all of this:
> - It’s changing the compile-time name resolution! The Swift name is
> foo(bar:), but it’s changing that to fooWithBar:!
>
> - It’s changing the signature! The argument took a String, but now it’s
> passing an NSString!
>
> - It’s not resolving the method at compile-time! It’s passing the modified
> method name and the arg list to some objc_msgSend() function, which resolves
> it dynamically in a way that user code can intercept and interpret at runtime!
>
> I’m just not seeing the conceptual difference here.
below the fold as far as the rest of the language is concerned. You could just
as well written what the importer synths up in Swift directly:
func foo(bar: String) {
unsafeBitCast(objc_msgSend, to: @convention(c) (AnyObject, Selector,
NSString) -> ().self)(self, "fooWithBar:", NSString(bar))
}
and the rest of the language would be none the wiser.
-Joe
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