Strategy for developing namespaced and non-namespaced versions of same PHP code

Question

I\'m maintaining library written for PHP 5.2 and I\'d like to create PHP 5.3-namespaced version of it. However, I\'d also keep non-namespaced version up to date until PHP 5.

Answer 1

Here's the best answer I think you're going to be able to find:

Step 1: Create a directory called 5.3 for every directory w/ php5.3 code in it and stick all 5.3-specific code in it.

Step 2: Take a class you want to put in a namespace and do this in 5.3/WebPage/Consolidator.inc.php:

namespace WebPage;
require_once 'WebPageConsolidator.inc.php';

class Consolidator extends \WebpageConsolidator
{
    public function __constructor()
    {
        echo "PHP 5.3 constructor.\n";

        parent::__constructor();
    }
}

Step 3: Use a strategy function to use the new PHP 5.3 code. Place in non-PHP5.3 findclass.inc.php:

// Copyright 2010-08-10 Theodore R. Smith 
// License: BSD License
function findProperClass($className)
{
    $namespaces = array('WebPage');

    $namespaceChar = '';
    if (PHP_VERSION_ID >= 50300)
    {
        // Search with Namespaces
        foreach ($namespaces as $namespace)
        {
            $className = "$namespace\\$className";
            if (class_exists($className))
            {
                return $className;
            }
        }

        $namespaceChar = "\\";
    }

    // It wasn't found in the namespaces (or we're using 5.2), let's search global namespace:
    foreach ($namespaces as $namespace)
    {
        $className = "$namespaceChar$namespace$className";
        if (class_exists($className))
        {
            return $className;
        }
    }

    throw new RuntimeException("Could not load find a suitable class named $className.");
}

Step 4: Rewrite your code to look like this:

= 50300)
{
        $includePrefix = '5.3/';
}

require_once $includePrefix . 'WebPageConsolidator.inc.php';

$className = findProperClass('Consolidator');
$consolidator = new $className;

// PHP 5.2 output: PHP 5.2 constructor.
// PHP 5.3 output: PHP 5.3 constructor. PHP 5.2 constructor.

That will work for you. It is a cludge performance-wise, but just a little, and will be done away with when you decide to stop supporting 5.3.