Casting method to block in Objective C - objective-c

Question

I'm using a framework that uses a huge amount of block arguments to emit events. Due to licensing I can't release code samples, but I can still get my point across with similar code. Lets say you have the following code:
- (void)begin
{
[MyService doSomething:^{
NSLog(#"Done.");
}];
}
This is fine, but the methods I'm dealing with have 14 block arguments, most of which take several parameters so it makes it very hard to read and difficult to test without creating repetitive boiler-plate code.
Is there a way I can point a block to an instance's method, something like:
- (void)doSomethingDelegate
{
NSLog(#"Done.");
}
- (void)begin
{
[MyService doSomething:CALLBACK(self, #selector(doSomethingDelegate))];
}
Where CALLBACK is a macro or native construct. Is this possible?

Answer 1

No, but you can declare local blocks:
- (void)begin
{
void (^callback)() = ^{ NSLog(#"Done."); };
[MyService doSomething:callback];
}
You could extend that to:
- (void)callbackImpl {
NSLog(#"Done.");
}
- (void)begin {
void (^callback)() = ^() { [self callbackImpl]; };
[MyService doSomething:callback];
}
And you could imagine a macro of the sort:
#define CALLBACK(name) void (^name)() = ^{ [self name##Impl]; };
It gets a little messier when you have arguments to the block, and you need to consider if you want a strong or weak reference to self in those blocks...

Answer 2

Since I also have to worry about arguments that are in a different from this is the best solution I've found so far:
#define wrapper(args, method) ^args { [self method]; }
- (void)onUpdatingDeviceWithMessage:(NSString *)message progress:(float)progress
{
}
- (void)begin
{
[MyService ...
onUpdatingDevice:wrapper((NSString *message, float progress),
onUpdatingDeviceWithMessage:message progress:progress)
}