PHP: 可变函数 - Manual


    
     
      <?php
      

     
     
      function
     
     
      foo
     
     
      () {
      

      echo
     
     
      "In foo()<br />\n"
     
     
      ;
      

      }
      

      

      function
     
     
      bar
     
     
      (
     
     
      $arg
     
     
      =
     
     
      ''
     
     
      )
      

      {
      

      echo
     
     
      "In bar(); argument was '
     
     
      $arg
     
     
      '.<br />\n"
     
     
      ;
      

      }
      

      

     
     
      // 使用 echo 的包装函数
      

     
     
      function
     
     
      echoit
     
     
      (
     
     
      $string
     
     
      )
      

      {
      

      echo
     
     
      $string
     
     
      ;
      

      }
      

      

     
     
      $func
     
     
      =
     
     
      'foo'
     
     
      ;
      

     
     
      $func
     
     
      ();
     
     
      // 调用 foo()
      

      

     
     
      $func
     
     
      =
     
     
      'bar'
     
     
      ;
      

     
     
      $func
     
     
      (
     
     
      'test'
     
     
      );
     
     
      // 调用 bar()
      

      

     
     
      $func
     
     
      =
     
     
      'echoit'
     
     
      ;
      

     
     
      $func
     
     
      (
     
     
      'test'
     
     
      );
     
     
      // 调用 echoit()
      

     
     
      ?>

niemans at pbsolo dot nl ¶

5 years ago


    
     While the documentation suggests that the use of a constant is similar to the use of a variable, there is an exception regarding variable functions. You cannot use a constant as the function name to call a variable function.
     

     

     const DEBUGME ='func';
     

     function func($s) { echo $s. "\n"; }
     

     

     DEBUGME('abc');  // results in a syntax error
     

     

     $call = DEBUGME;
     

     $call('abc');          // does the job
     

     

     But you can use a constant as an argument to a function. Here's a simple workaround when you need to call a variable constant function:
     

     

     function dynamic($what, $with)
     

     {
     

     $what($with);
     

     }
     

     dynamic(DEBUGME, 'abc');
     

     

     This makes sense to me to hide API's and/or long (complicated) static calls.
     

     Enjoy!

rnealxp at yahoo dot com ¶

4 years ago


    
     
      <?php
      

     
     
      /*
      

      You might have found yourself at this php variable functions page because, like me, you wanted to pass functions
      

      around like objects to client objects as you can in JavaScript. The issue I ran into was although
      

      I could call a function using a variable like this " $v(); "...I could not do it like this " $obj->p() " where
      

      'p' is a property containing the name of the method to call. Did not want to save my property off to a variable prior
      

      to making my call: " $v = $obj->p; $v(); "; even if one finds a way, the below applies...
      

      

      I credit this expanded work to this person: tatarynowicz at gmail dot com;
      

      without them I would not have gotten here.
      

      */
      

     
     
      interface
     
     
      iface_dynamic_members
     
     
      {
      

     
     
      //Use of this interface enables type-hinting for objects that implement it.
      

     
     
      public function
     
     
      __call
     
     
      (
     
     
      $name
     
     
      ,
     
     
      $args
     
     
      );
      

      public function
     
     
      __set
     
     
      (
     
     
      $name
     
     
      ,
     
     
      $value
     
     
      );
      

      public function
     
     
      quietly_fail
     
     
      ():
     
     
      bool
     
     
      ;
      

      }
      

      trait
     
     
      trait_has_dynamic_members
     
     
      {
      

     
     
      //Implementing these magic methods in the form of a trait, frees the client object up
      

      //so it can still inherit from a parent-class.
      

     
     
      public function
     
     
      __call
     
     
      (
     
     
      $name
     
     
      ,
     
     
      $args
     
     
      ) {
      

      if (
     
     
      is_callable
     
     
      (
     
     
      $this
     
     
      ->
     
     
      $name
     
     
      )) {
      

      return
     
     
      call_user_func
     
     
      (
     
     
      $this
     
     
      ->
     
     
      $name
     
     
      ,
     
     
      $args
     
     
      );
      

      }
      

      else {
      

     
     
      //Your dynamic-membered object can declare itself as willing to ignore non-existent method calls or not.
      

     
     
      if(
     
     
      $this
     
     
      ->
     
     
      quietly_fail
     
     
      ()===
     
     
      true
     
     
      ){
      

      echo
     
     
      'Method does not exist, but I do not mind.'
     
     
      ;
      

      }else{
      

      echo
     
     
      'Method does not exist, I consider this a bug.'
     
     
      ;
      

      }
      

      }
      

      }
      

      public function
     
     
      __set
     
     
      (
     
     
      $name
     
     
      ,
     
     
      $value
     
     
      ) {
      

     
     
      $this
     
     
      ->
     
     
      $name
     
     
      =
     
     
      is_callable
     
     
      (
     
     
      $value
     
     
      ) ?
     
     
      $value
     
     
      ->
     
     
      bindTo
     
     
      (
     
     
      $this
     
     
      ,
     
     
      $this
     
     
      ):
     
     
      $value
     
     
      ;
     
     
      //Assignment using ternary operator.
      

     
     
      }
      

      }
      

      abstract class
     
     
      MBR_ATTR
     
     
      {
      

     
     
      //A class full of attributes that objects can take on; abstract since not to be instantiated (If I could make it "final" as well, I would).
      

     
     
      public static function
     
     
      is_a_walker
     
     
      (
     
     
      iface_dynamic_members $obj
     
     
      , ?
     
     
      string $walker_type
     
     
      =
     
     
      'normal pace'
     
     
      ){
      

     
     
      $obj
     
     
      ->
     
     
      walker_type
     
     
      =
     
     
      $walker_type
     
     
      ;
      

     
     
      $obj
     
     
      ->
     
     
      walker_walk
     
     
      = function() {
      

      return
     
     
      "I am walking
     
     
      {
     
     
      $this
     
     
      ->
     
     
      walker_type
     
     
      }
     
     
      ."
     
     
      ;
      

      };
      

      }
      

      public static function
     
     
      is_a_runner
     
     
      (
     
     
      iface_dynamic_members $obj
     
     
      ,
     
     
      string $runner_type
     
     
      ){
      

     
     
      $obj
     
     
      ->
     
     
      runner_type
     
     
      =
     
     
      $runner_type
     
     
      ;
      

     
     
      $obj
     
     
      ->
     
     
      runner_run
     
     
      = function() {
      

      return
     
     
      "I am running
     
     
      {
     
     
      $this
     
     
      ->
     
     
      runner_type
     
     
      }
     
     
      ."
     
     
      ;
      

      };
      

     
     
      self
     
     
      ::
     
     
      is_a_walker
     
     
      (
     
     
      $obj
     
     
      );
     
     
      //If can run, also can walk.
      

     
     
      }
      

      }
      

      class
     
     
      cls_partly_dynamic
     
     
      implements
     
     
      iface_dynamic_members
     
     
      {
      

      use
     
     
      trait_has_dynamic_members
     
     
      ;
      

      public function
     
     
      quietly_fail
     
     
      ():
     
     
      bool
     
     
      {
      

      return
     
     
      true
     
     
      ;
      

      }
      

      }
      

     
     
      // Report all errors except E_NOTICE
      

     
     
      error_reporting
     
     
      (
     
     
      E_ALL
     
     
      & ~
     
     
      E_NOTICE
     
     
      );
     
     
      //Enable all error-reporting except notices.
      

      //----
      

      //config runner object...
      

     
     
      $obj_runner
     
     
      = new
     
     
      cls_partly_dynamic
     
     
      ();
      

     
     
      MBR_ATTR
     
     
      ::
     
     
      is_a_runner
     
     
      (
     
     
      $obj_runner
     
     
      ,
     
     
      'fast'
     
     
      );
      

     
     
      $obj_runner
     
     
      ->
     
     
      runner_type
     
     
      =
     
     
      'a bit slow'
     
     
      ;
      

     
     
      //----
      

      //config walker object...
      

     
     
      $obj_walker
     
     
      = new
     
     
      cls_partly_dynamic
     
     
      ();
      

     
     
      MBR_ATTR
     
     
      ::
     
     
      is_a_walker
     
     
      (
     
     
      $obj_walker
     
     
      ,
     
     
      'slow'
     
     
      );
      

     
     
      $obj_walker
     
     
      ->
     
     
      walker_type
     
     
      =
     
     
      'super fast'
     
     
      ;
      

     
     
      //----
      

      //Do stuff...
      

     
     
      echo
     
     
      'walker in action...'
     
     
      .
     
     
      '<br>'
     
     
      ;
      

      echo
     
     
      $obj_walker
     
     
      ->
     
     
      walker_walk
     
     
      () .
     
     
      '<br>'
     
     
      ;
      

      echo
     
     
      '<br>'
     
     
      ;
      

      echo
     
     
      'runner in action...'
     
     
      .
     
     
      '<br>'
     
     
      ;
      

      echo
     
     
      $obj_runner
     
     
      ->
     
     
      walker_walk
     
     
      () .
     
     
      '<br>'
     
     
      ;
      

      echo
     
     
      $obj_runner
     
     
      ->
     
     
      runner_run
     
     
      () .
     
     
      '<br>'
     
     
      ;
      

      echo
     
     
      $obj_runner
     
     
      ->
     
     
      xxx
     
     
      () .
     
     
      '<br>'
     
     
      ;
     
     
      //Try calling a non-existent method.
      

      //I would agree that the above approach/technique is not always ideal, particulary due to the loss of code-completion in your
      

      //IDE of choice; I would tend to use this approach for dynamic-programming in response to the user dictating processing steps via a UI.
      

     
     
      ?>

Anonymous ¶

13 years ago


    
     $ wget
     
      http://www.php.net/get/php_manual_en.tar.gz/from/a/mirror
     
     

     $ grep -l "\$\.\.\." php-chunked-xhtml/function.*.html
     

     

     List of functions that accept variable arguments.
     

     
      <?php
      

      array_diff_assoc
     
     
      ()
      

     
     
      array_diff_key
     
     
      ()
      

     
     
      array_diff_uassoc
     
     
      ()
      

      array()
      

     
     
      array_intersect_ukey
     
     
      ()
      

     
     
      array_map
     
     
      ()
      

     
     
      array_merge
     
     
      ()
      

     
     
      array_merge_recursive
     
     
      ()
      

     
     
      array_multisort
     
     
      ()
      

     
     
      array_push
     
     
      ()
      

     
     
      array_replace
     
     
      ()
      

     
     
      array_replace_recursive
     
     
      ()
      

     
     
      array_unshift
     
     
      ()
      

     
     
      call_user_func
     
     
      ()
      

     
     
      call_user_method
     
     
      ()
      

     
     
      compact
     
     
      ()
      

     
     
      dba_open
     
     
      ()
      

     
     
      dba_popen
     
     
      ()
      

      echo()
      

     
     
      forward_static_call
     
     
      ()
      

     
     
      fprintf
     
     
      ()
      

     
     
      fscanf
     
     
      ()
      

     
     
      httprequestpool_construct
     
     
      ()
      

     
     
      ibase_execute
     
     
      ()
      

     
     
      ibase_set_event_handler
     
     
      ()
      

     
     
      ibase_wait_event
     
     
      ()
      

      isset()
      

      list()
      

     
     
      maxdb_stmt_bind_param
     
     
      ()
      

     
     
      maxdb_stmt_bind_result
     
     
      ()
      

     
     
      mb_convert_variables
     
     
      ()
      

     
     
      newt_checkbox_tree_add_item
     
     
      ()
      

     
     
      newt_grid_h_close_stacked
     
     
      ()
      

     
     
      newt_grid_h_stacked
     
     
      ()
      

     
     
      newt_grid_v_close_stacked
     
     
      ()
      

     
     
      newt_grid_v_stacked
     
     
      ()
      

     
     
      newt_win_choice
     
     
      ()
      

     
     
      newt_win_entries
     
     
      ()
      

     
     
      newt_win_menu
     
     
      ()
      

     
     
      newt_win_message
     
     
      ()
      

     
     
      newt_win_ternary
     
     
      ()
      

     
     
      pack
     
     
      ()
      

     
     
      printf
     
     
      ()
      

     
     
      register_shutdown_function
     
     
      ()
      

     
     
      register_tick_function
     
     
      ()
      

     
     
      session_register
     
     
      ()
      

     
     
      setlocale
     
     
      ()
      

     
     
      sprintf
     
     
      ()
      

     
     
      sscanf
     
     
      ()
      

      unset()
      

     
     
      var_dump
     
     
      ()
      

     
     
      w32api_deftype
     
     
      ()
      

     
     
      w32api_init_dtype
     
     
      ()
      

     
     
      w32api_invoke_function
     
     
      ()
      

     
     
      wddx_add_vars
     
     
      ()
      

     
     
      wddx_serialize_vars
     
     
      ()
      

     
     
      ?>

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