tap:方法是从Ruby借用的。它还支持来自RubyGem的tapp，用于打印调试用例。
让我们使用CocoaPods。
# Podfile
pod 'NSObject-Tap'$ pod install或者复制两个文件NSObject+Tap.{h,m}到您的项目中。
然后，导入头文件。
#import "NSObject+Tap.h"初始化
NSArray *array = [[NSMutableArray array] tap:^(NSMutableArray *x) {
[x addObject:@1];
[x addObject:@2];
[x addObject:@3];
}];Person *person = [[[Person alloc] init] tap:^(Person *p) {
p.name = @"Your Name";
p.age = 20;
p.address = @"Kyoto, Japan";
}];更简洁的代码，减少局部变量
// NSUserDefaults
// before 1
[[NSUserDefaults standardUserDefaults] setObject:@1 forKey:@"1"];
[[NSUserDefaults standardUserDefaults] setObject:@2 forKey:@"2"];
[[NSUserDefaults standardUserDefaults] setObject:@3 forKey:@"3"];
// before 2
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:@1 forKey:@"1"];
[defaults setObject:@2 forKey:@"2"];
[defaults setObject:@3 forKey:@"3"];
// after
[[NSUserDefaults standardUserDefaults] tap:^(NSUserDefaults *x) {
[x setObject:@1 forKey:@"1"];
[x setObject:@2 forKey:@"2"];
[x setObject:@3 forKey:@"3"];
}];
// NSNotificationCenter
[[NSNotificationCenter defaultCenter] tap:^(id x) {
[x addObserver:self
selector:@selector(willEnterForeground:)
name:UIApplicationWillEnterForegroundNotification
object:nil];
[x addObserver:self
selector:@selector(didEnterBackground:)
name:UIApplicationDidEnterBackgroundNotification
object:nil];
}]使用tapp
// Outputs "Hello, world!"
NSString *helloWorld = [@"Hello, world!" tapp];
// Outputs like "<NSObject: 0x7ffbf0402f10>"
id object = [[[NSObject alloc] init] tapp];
// Between method chains
NSArray *filtered = [[[@[ @1, @2, @3, @4, @5 ] tapp] filteredArrayUsingPredicate:evenPredicate] tapp];