升级遗留PHP代码 - 这些表达式是否相同？

Question

I am currently tasked with upgrading a library of pre-PHP5 code to conform with modern runtimes.

The library contains several uses of the following pattern:

$foo = new foo();
foreach($foo as &$ref) {
    // Do something with $ref
}

According to the PHP documentation, this is illegal as of PHP 5.2, and will throw an exception (http://php.net/manual/en/migration52.error-messages.php)

My question is, how do I change the syntax to maintain the same functionality, while conforming to PHP 5.2+ standards? Does it suffice if I simply remove the ampersand?

$foo = new foo();
foreach($foo as $ref) {
    // Do something with $ref
}

Answer 1

For iterating through an object and its properties and modifying the original object you can use the foreach() like this:

 // Iterate over the object $foo
 foreach ($foo as $key => $ref) {

   // Some operation
   $newRef = $ref;

   // Change the original object
   $foo->$key = $newRef;
   }

This will allow you to iterate only over the visible properties (as normally desirable). However, since you are migrating code into OOP, it might be desirable to just put the abstraction at a different level. The code above is good for arrays, but in OOP this is much more normal. Again, it depends on the case:

// Create the object
$foo = new foo();

// Delegate the iteration to the inner method
$foo->performAction();

This makes the code calling the performAction() NOT to need to know about the properties of foo(), letting the object to handle its properties. Why would the house need to know about the door's knob? That's the door responsability.