Also, there is some info on: http://fuckingblocksyntax.com

/// returnType (^blockName)(parameterTypes) = ^returnType(parameters) {...};

void (^printXAndY)(int) = ^(int y) {
    printf("%d %d\n", x, y);
};

printXAndY(4);

void (^blockName)(void) = ^void(void) {
  printf("hello world");
};

blockName();

object.property = ^(Foo* foo) {
  [foo doSmth];
};