什么是PHP中的函数GLOBAL的范围？

Question

i have 3 Files, declaring a namespace (minimalistic example):

<?php //f1.php
  namespace Sheet;
  $base = [1,2,3];
?>

<?php // f2.php
  namespace Sheet;
  require_once('f1.php');
  var_dump($base);                                 // ----> array(1,2,3)
  class Reader {
    public static function get($pos) {
      GLOBAL $base;
      var_dump($base);                             // ---->  NULL
      foreach ($base as $idx => $val) {
        if ($pos == ($idx +1)) return $base[$idx];
      }
      return null;
    }
  }
?>

<?php //test.php
  namespace Test;
  require_once('f2.php');
  print \Sheet\Reader::get(1);   // expected:  '2'
?>

Somehow, i get an invalid argument exception in foreach.

I wonder whats the scope for the GLOBAL declaration is - any ideas?

edit: how can i access that variable within the function get() in a more convenient way?

Answer 1

Push the variable into the $GLOBALS array to be accessed. Just make sure, there is no name clash. Casting to object overwrites previous stuff, so make sure, you optimise this part. I used __NAMESPACE__ in both places, since the accessing class is in the same.

<?php //f1.php
  namespace Sheet;
  $base = [1,2,3];

  // globalise objectified var!
  $GLOBALS['NSvars'] = [__NAMESPACE__ => (object)['base' => $base]]; 
?>

<?php // f2.php
  namespace Sheet;
  require_once('f1.php');
  var_dump($base);                                 // ----> array(1,2,3)
  class Reader {
    public static function get($pos) {
      GLOBAL $NSvars;
      $base = $NSvars[__NAMESPACE__]->base;        // use the global
      var_dump($base);                             // ---->  array(1,2,3)
      foreach ($base as $idx => $val) {
        if ($pos == ($idx +1)) return $base[$idx];
      }
      return null;
    }
  }
?>

<?php //test.php
  namespace Test;
  require_once('f2.php');
  print \Sheet\Reader::get(1);   // expected:  '2'
?>

a more object oriented approach:

<?php //f1.php
  namespace Sheet;
  abstract class Defs {
    public static $base = [1,2,3];
  }
?>

<?php // f2.php
  namespace Sheet;
  require_once('f1.php');
  class Reader {
    public static function get($pos) {
      foreach (Defs::$base as $idx => $val) {
        if ($pos == ($idx +1)) return Defs::$base[$idx];
      }
      return null;
    }
  }
?>

<?php //test.php
  namespace Test;
  require_once('f2.php');
  print \Sheet\Reader::get(1);   // expected:  '2'
?>