SimpleBlockComposition.m

#import "SimpleBlockComposition.h"

typedef typeof(unsigned long(^)(unsigned long)) block;
typedef typeof(block *) block_t;
typedef typeof(block(^)(block)) block_object;

static block (^compose)(block, block) = ^ (block composition, block component) {
    block temp_comp = composition;
    block new_comp = ^ (unsigned long c) { printf("composing block chain...\n"); return component(temp_comp(c)); };
    return new_comp;
};

static unsigned long (^(^(^objects_iterator)(void))(block))(void) = ^{
    __block unsigned long audio_state_cond = 0UL;
    static volatile block object_composition = ^ unsigned long (unsigned long c) { printf("(1) block %lu\n", c); return c; };
    __block restrict block_t object_composition_ptr = &object_composition;
    return ^ (block object) {
        object_composition = compose(object_composition, object);
        return ^{
            return (*object_composition_ptr)(audio_state_cond = -~audio_state_cond);
        };
    };
};

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    
    unsigned long(^(^asdf)(block))(void) = objects_iterator();
    unsigned long(^wxyz)(void) = asdf(^ (unsigned long lu) { printf("(B) lu = %lu\n", lu); return lu; });
    wxyz();
    unsigned long(^mnop)(void) = asdf(^ (unsigned long lu) { printf("(A) lu = %lu\n", lu); return lu; });
    wxyz();
}

@end