浅谈PHP闭包 Closure和Callable

Closure 必须是匿名函数,  callable 同时还可以为可调用函数名

  1. function func1(callable $callable)
  2. {
  3.     return $callable();
  4. }
  6. function func2(Closure $closure)
  7. {
  8.     return $closure();
  9. }
  11. function test()
  12. {
  13.     echo "test\n";
  14. }
  16. $demo =  function (){
  17.     echo 'demo';
  18. };
  20. func1('test'); //输出 test
  21. func1($demo);//输出demo
  23. //报错 Fatal error: Uncaught TypeError: func2(): Argument #1 ($closure) must be of type Closure, string given, called
  24. func2('test');
  26. func2($demo);//输出demo

 

  1. <?php
  3. function func1(callable $callable)
  4. {
  5.     return $callable();
  6. }
  8. function func2(Closure $closure)
  9. {
  10.     return $closure();
  11. }
  13. function test()
  14. {
  15.     echo "test\n";
  16. }
  18. $demo =  function (){
  19.     echo 'demo';
  20. };
  23. //报错 Fatal error: Uncaught TypeError: func2(): Argument #1 ($closure) must be of type Closure, string given, called
  24. func2('test');
  27. func2(Closure::fromCallable('test'));//输出 test
  1. /**
  2.  * 声明一个a类
  3.  */
  4. class a{
  5.     /**
  6.      * @var int 这里声明一个a成员变量 初始值为1
  7.      */
  8.     public $a = 1;
  9. }
  11. //这里声明一个闭包函数 函数输出this指向a变量
  12. $closure = function (){
  13.     echo $this->a;
  14.     $this->a = 3;
  15. };
  16. $a = new a; //实例化a类
  18. //调用闭包中的bindTo方法,将闭包函数内的this指向到实例a
  19. $closure = $closure->bindTo($a);
  21. //执行闭包
  22. $closure();//输出1
  23. var_dump($a->a);//输出3
  1. /**
  2.  * 声明一个a类
  3.  */
  4. class a{
  5.     /**
  6.      * @var int 这里声明一个a成员变量 初始值为1
  7.      */
  8.     public $a = 1;
  9.     protected $b=2;
  10.     private $c = 3;
  12.     public function a()
  13.     {
  14.         echo $this->a;
  15.     }
  17.     protected function b()
  18.     {
  19.         echo $this->b;
  20.     }
  22.     private function c()
  23.     {
  24.         echo $this->c;
  25.     }
  26. }
  28. //这里声明一个闭包函数 函数输出this指向a变量
  29. $closure = function (){
  30.     echo $this->a;//输出1
  31.     echo $this->b;//报错 Fatal error: Uncaught Error: Cannot access protected property a::$b
  32.     echo $this->c;//报错 Fatal error: Uncaught Error: Cannot access private property a::$c
  33.     echo $this->a();//输出1
  34.     echo $this->b();//报错 Fatal error: Uncaught Error: Call to protected method a::b() from scope Closure
  35.     echo $this->c();//报错 Fatal error: Uncaught Error: Call to private method a::c() from scope Closure
  36. };
  37. $a = new a; //实例化a类
  39. //调用闭包中的bindTo方法,将闭包函数内的this指向到实例a
  40. $closure = $closure->bindTo($a);
  42. //执行闭包
  43. $closure();
  1. $closure = $closure->bindTo($a,'a');

这个时候再执行上面的代码

  1. /**
  2.  * 声明一个a类
  3.  */
  4. class a{
  5.     /**
  6.      * @var int 这里声明一个a成员变量 初始值为1
  7.      */
  8.     public $a = 1;
  9.     protected $b=2;
  10.     private $c = 3;
  12.     public function a()
  13.     {
  14.         echo $this->a;
  15.     }
  17.     protected function b()
  18.     {
  19.         echo $this->b;
  20.     }
  22.     private function c()
  23.     {
  24.         echo $this->c;
  25.     }
  26. }
  28. //这里声明一个闭包函数 函数输出this指向a变量
  29. $closure = function (){
  30.     echo $this->a;//输出1
  31.     echo $this->b;//输出2
  32.     echo $this->c;//输出3
  33.      $this->a();//输出1
  34.      $this->b();//输出2
  35.      $this->c();//输出3
  36. };
  37. $a = new a; //实例化a类
  39. //调用闭包中的bindTo方法,将闭包函数内的this指向到实例a
  40. $closure = $closure->bindTo($a,'a');
  42. //执行闭包
  43. $closure();
  1. $closure = Closure::bind($closure,$a,'a');

执行效果和上面的bindTo方法结果一样

  1. /**
  2.  * 声明一个a类
  3.  */
  4. class a{
  5.     /**
  6.      * @var int 这里声明一个a成员变量 初始值为1
  7.      */
  8.     public $a = 1;
  9.     protected $b=2;
  10.     private $c = 3;
  12.     public function a()
  13.     {
  14.         echo $this->a;
  15.     }
  17.     protected function b()
  18.     {
  19.         echo $this->b;
  20.     }
  22.     private function c()
  23.     {
  24.         echo $this->c;
  25.     }
  27.     public static function t()
  28.     {
  30.     }
  31. }
  33. function test()
  34. {
  36. };
  37. $a = new a;
  38. is_callable('test');//True
  39. is_callable(function (){});//True
  40. is_callable([$a,'a']);//True
  41. is_callable(['a','t']);//True
  1. /**
  2.  * 声明一个a类
  3.  */
  4. class a{
  5.     /**
  6.      * @var int 这里声明一个a成员变量 初始值为1
  7.      */
  8.     public $a = 1;
  9.     protected $b=2;
  10.     private $c = 3;
  12.     public function a()
  13.     {
  14.         echo $this->a;
  15.     }
  17.     protected function b()
  18.     {
  19.         echo $this->b;
  20.     }
  22.     private function c()
  23.     {
  24.         echo $this->c;
  25.     }
  27.     public static function t()
  28.     {
  29.         echo 1;
  30.     }
  31. }
  33. function test()
  34. {
  35.  echo 'test';
  36. };
  37. $a = new a;
  39. $closure = Closure::fromCallable('test');
  40. $closure();//输出test
  42. $closure = Closure::fromCallable(['a','t']);
  43. $closure();//输出1
  45. $closure = Closure::fromCallable([$a,'a']);
  46. $closure();//输出1