局部变量

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

property

@property (nonatomic, copy, nullability) returnType (^blockName)(parameterTypes);

实例方法

- (void)someMethodThatTakesABlock:(returnType (^nullability)(parameterTypes))blockName;

方法调用

[someObject someMethodThatTakesABlock:^returnType (parameters) {...}];

typedef

typedef returnType (^TypeName)(parameterTypes);