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sneskid at hotmail dot com
10 years ago
(v5.1.4)
One cool thing about var_dump is it shows which variables are references (when dumping arrays), symbolized by '∫' for int/null, and by '&' for boolean/double/string/array/object. I don't know why the difference in symmmmbolism.
After playing around I found a better way to implement detaching (twas by accident). var_dump can show what's going on.

<?php
function &detach($v=null){return $v;}

$A=array('x' => 123, 'y' => 321);
$A['x'] = &$A['x'];
var_dump($A);
/* x became it's own reference...
array(2) {
  ["x"]=> ∫(123)
  ["y"]=> int(321)
}*/

$A['y']=&$A['x'];
var_dump($A);
/* now both are references
array(2) {
  ["x"]=> ∫(123)
  ["y"]=> ∫(123)
}*/

$z = 'hi';
$A['y']=&detach(&$z);
var_dump($A);
/* x is still a reference, y and z share
array(2) {
  ["x"]=> ∫(123)
  ["y"]=> &string(2) "hi"
}*/

$A['x'] = $A['x'];
$A['y']=&detach();
var_dump($A,$z);
/* x returned to normal, y is on its own, z is still "hi"
array(2) {
  ["x"]=> int(123)
  ["y"]=> NULL
}*/
?>

For detach to work you need to use '&' in the function declaration, and every time you call it.

Use this when you know a variable is a reference, and you want to assign a new value without effecting other vars referencing that piece of memory. You can initialize it with a new constant value, or variable, or new reference all in once step.

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