iOS-block的定义

变量

returnType (^blockName)(parameterTypes) = ^returnType(parameters) {...};
As a property:

属性

@property (nonatomic, copy, nullability) returnType (^blockName)(parameterTypes);
As a method parameter:

方法

- (void)someMethodThatTakesABlock:(returnType (^nullability)(parameterTypes))blockName;
As an argument to a method call:

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

typedef:

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