Objective-Cでメソッドチェーンやる奴

hoge.m

#import <Cocoa/Cocoa.h>

@class Hoge;

typedef Hoge *(^setter)(int);

@interface Hoge : NSObject
@property int a,b;
@property (nonatomic, readonly, copy) setter setA;
@property (nonatomic, readonly, copy) setter setB;
@end

@implementation Hoge

@synthesize a,b;

-(id)init
{
  if(self = [super init]) {
	self->a = 1; self->b = 2;
  }
  return self;
}

-(setter)setA
{
  __block __weak Hoge *o = self;
  return [^Hoge *(int na) {
		o.a = na;
		return o;
	} copy];
}
-(setter)setB
{
  __block __weak Hoge *o = self;
  return [^Hoge *(int nb) {
		o.b = nb;
		return o;
	} copy];
}

@end

int main()
{
	Hoge *obj = [[Hoge alloc] init];
	NSLog(@"a = %d, b = %d", obj.a, obj.b);
	obj.setA(23).setB(56);
	NSLog(@"a = %d, b = %d", obj.a, obj.b);
	return 0;
}