Reference Passing in PHP

Transcript

1. Reference Passing in PHP Tamal Saha
2. Pass Scalar Types by Reference
3. Pass Scalar Types by Reference 5 5 <?php $instance = 5; $assigned = $instance; $referenced =& $instance; $instance $assigned $referenced
4. Pass Scalar Types by Reference 10 5 <?php $instance = 5; $assigned = $instance; $referenced =& $instance; $instance = 10; $instance $assigned $referenced
5. Pass Scalar Types by Reference null 5 <?php $instance = 5; $assigned = $instance; $referenced =& $instance; $instance = 10; $instance = null; $instance $assigned $referenced
6. Pass Scalar Types by Reference null 5 <?php $instance = 5; $assigned = $instance; $referenced =& $instance; $instance = 10; $instance = null; echo '$instance = '; var_dump($instance); echo "\n", '$assigned = '; var_dump($assigned); echo "\n", '$referenced = '; var_dump($referenced); $instance $assigned $referenced
7. Pass Objects by Reference
8. Pass Objects by Reference obj-id obj-id <?php class SimpleClass { public $deviceToken = 'original'; } $instance = new SimpleClass(); $assigned = $instance; $referenced =& $instance; $instance $assigned $referenced deviceToken: original
9. Pass Objects by Reference obj-id obj-id <?php class SimpleClass { public $deviceToken = 'original'; } $instance = new SimpleClass(); $assigned = $instance; $referenced =& $instance; $instance->deviceToken = 'modified'; $instance $assigned $referenced deviceToken: modified
10. Pass Objects by Reference null obj-id <?php class SimpleClass { public $deviceToken = 'original'; } $instance = new SimpleClass(); $assigned = $instance; $referenced =& $instance; $instance->deviceToken = 'modified'; $instance = null; $instance $assigned $referenced deviceToken: modified
11. Pass Objects by Reference null obj-id <?php class SimpleClass { public $deviceToken = 'original'; } $instance = new SimpleClass(); $assigned = $instance; $referenced =& $instance; $instance->deviceToken = 'modified'; $instance = null; echo '$instance = '; var_dump($instance); echo "\n", '$assigned = '; var_dump($assigned); echo "\n", '$referenced = '; var_dump($referenced); $instance $assigned $referenced deviceToken: modified
12. Pass Array by Reference
13. Pass Array by Reference [0] = 1 [1] = 2 [0] = 1 [1] = 2 <?php $instance = array(1, 2); $assigned = $instance; $referenced =& $instance; $instance $assigned $referenced
14. Pass Array by Reference [0] = 6 [1] = 2 [0] = 1 [1] = 2 <?php $instance = array(1, 2); $assigned = $instance; $referenced =& $instance; $instance[0] = 6; $instance $assigned $referenced
15. Pass Array by Reference [0] = 6 [1] = 2 [2] = 3 [0] = 1 [1] = 2 <?php $instance = array(1, 2); $assigned = $instance; $referenced =& $instance; $instance[0] = 6; array_push($instance, 3); $instance $assigned $referenced
16. Pass Array by Reference null null null [0] = 1 [1] = 2 <?php $instance = array(1, 2); $assigned = $instance; $referenced =& $instance; $instance[0] = 6; array_push($instance, 3); $instance = null; $instance $assigned $referenced
17. Pass Array by Reference null null null [0] = 1 [1] = 2 <?php $instance = array(1, 2); $assigned = $instance; $referenced =& $instance; $instance[0] = 6; array_push($instance, 3); $instance = null; $instance $assigned $referenced
18. Pass Array by Reference null null null [0] = 1 [1] = 2 <?php $instance = array(1, 2); $assigned = $instance; $referenced =& $instance; $instance[0] = 6; array_push($instance, 3); $instance = null; echo "\n", '$instance = '; var_dump($instance); echo "\n", '$assigned = '; var_dump($assigned); echo "\n", '$referenced = '; var_dump($referenced); $instance $assigned $referenced