Block composition

block_composition.m

typedef const bool (^ __strong object_block)(const bool);
object_block object_blk = ^ bool (const bool b) {
    printf("object_blk state == %s\n", (b) ? "TRUE" : "FALSE");
    return b;
};
object_block object_blk_2 = ^ bool (const bool b) {
    printf("object_blk_2 state == %s\n", (b) ? "TRUE" : "FALSE");
    return b;
};
object_block object_blk_3 = ^ bool (const bool b) {
    printf("object_blk_3 state == %s\n", (b) ? "TRUE" : "FALSE");
    return b;
};

object_block (^object_blk_composition)(object_block, object_block) = ^ (object_block object_blk_a, object_block object_blk_b) {
    return ^ bool (const bool b) {
        return object_blk_b(object_blk_a(b));
    };
};

static bool (^(^(^audio_controller_)(const _Nonnull audio_state))(object_block))(void) = ^ (const audio_state _Nonnull state) {
    static object_block object_composition = ^ bool (bool cond) { return cond; };
    static retained_object object_composition_t = &object_composition;
    return ^ (object_block object) {
        *object_composition_t = object_blk_composition(object, *object_composition_t);
        return ^ bool {
            return (*object_composition_t)(state());
        };
    };
};

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    
    bool (^(^audio_controller_ref)(object_block))(void) = audio_controller_(audio_state_ref_init(audio_engine(audio_source(audio_renderer())), audio_session()));
    audio_controller_ref(object_blk);     // Add a block to the composition
    audio_controller_ref(object_blk_2);   // Add another block to the composition
    audio_controller_ref(object_blk_3)(); // Add one more block to the composition and invoke the composition block
}