> On Nov 10, 2017, at 2:57 PM, Joe Groff <[email protected]> wrote:
>
>> On Nov 10, 2017, at 12:37 PM, Charles Srstka <[email protected]
>> <mailto:[email protected]>> wrote:
>>
>>> On Nov 10, 2017, at 12:04 PM, Joe Groff via swift-evolution
>>> <[email protected] <mailto:[email protected]>> wrote:
>>>
>>> I don't like the idea of some calls having wildly different semantics from
>>> others; it's difficult enough to tell what exactly a call might be doing
>>> already. Since we also lack the more obvious static "Callable" protocol
>>> idea to give even well-typed call syntax to user-defined types, this also
>>> seems like it'd be easily abused for that purpose too.
>>
>> We already have that though, with the Objective-C bridge. How is the
>> proposed behavior here more wildly different than the semantics of
>> non-@objc, @objc, and @objc dynamic calls?
>
> The language semantics aren't any different for non-@objc or @objc calls. The
> dispatch mechanism is an implementation detail. `dynamic` admits the
> possibility of late binding to change the method implementation dynamically,
> but doesn't change the type system behavior of the method, or radically
> change the implementation mechanism; it's still ultimately an indirect call,
> it doesn't turn your argument list into a dictionary that can be arbitrarily
> interpreted by user code.
>
> -Joe
You sure about that? ;-)
MyObject.h:
#import <Foundation/Foundation.h>
@interface MyObject : NSObject
@property (nonatomic, copy) void (^callback)(NSDictionary *);
@end
@interface MyObject (MyCategory)
- (void)foo:(NSString *)foo bar:(NSString *)bar;
@end
MyObject.m:
#import "MyObject.h"
@implementation MyObject
- (void)baz:(NSString *)baz qux:(NSString *)qux {}
- (NSMethodSignature *)methodSignatureForSelector:(SEL)selector {
if (selector == @selector(foo:bar:)) {
return [super methodSignatureForSelector:@selector(baz:qux:)];
} else {
return [super methodSignatureForSelector:selector];
}
}
- (void)forwardInvocation:(NSInvocation *)invocation {
NSString *name = NSStringFromSelector(invocation.selector);
NSMutableArray *args = [NSMutableArray new];
for (NSUInteger i = 2; i < invocation.methodSignature.numberOfArguments;
i++) {
__unsafe_unretained id obj = nil;
[invocation getArgument:&obj atIndex:i];
[args addObject:obj];
}
self.callback(@{ @"name" : name, @"arguments" : args });
}
@end
main.swift:
import Foundation
let obj = MyObject()
obj.callback = { dict in
print("got this dictionary: \(dict as? [String : Any] ?? [:])")
}
obj.foo("Foo", bar: "Baz”)
Charles
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