gistfile1.m

#import <Foundation/Foundation.h>

@protocol Foo
@property (readonly, nonatomic) int blah;
@end

typedef void (^bk)(void);
@interface Foo : NSObject<Foo>
{ int v; }
- (bk)makeBlock:(id<Foo>)otherFoo;
@end

@implementation Foo
- (int)blah {
    NSLog(@"Blah");
    return 1;
}

- (bk)makeBlock:(id<Foo>)otherFoo {
    return [^{ self->v = otherFoo.blah; } copy];
}
@end


bk mkBlock(Foo* f) {
    return [^{ [f blah]; } copy];
}

int main(int argc, char **argv) {
    NSAutoreleasePool *pool __attribute__((unused)) = [NSAutoreleasePool new];

    Foo *f = [Foo new], *g = [Foo new];

    bk b = [f makeBlock:g];
    b();

    return 0;
}