Example of how to use the Symfony Config component

gistfile1.php

<?php

// Load application-specific configuration
try {
    $basepath = __DIR__ . '/config';
    $configuration = Yaml::parse($basepath . '/config.yml');
} catch (\InvalidArgumentException $exception) {
    exit("Are you sure the configuration files exist?");
}

// Use a Symfony ConfigurationInterface object to specify the *.yml format
$yamlConfiguration = new \Configuration();

// Process the configuration files (merge one-or-more *.yml files)
$processor = new Processor();
$configuration = $processor->processConfiguration(
    $yamlConfiguration,
    array($configuration) // As many *.yml files as required
);

/*
 * The class to handle the *.yml configuration should look
 * something like this...
 */

use Symfony\Component\Config\Definition\ConfigurationInterface;
use Symfony\Component\Config\Definition\Builder\TreeBuilder;

class Configuration
{
    /**
     * @return TreeBuilder
     */
    public function getConfigTreeBuilder()
    {
        $treeBuilder = new TreeBuilder();
        $rootNode = $treeBuilder->root('arbitary');

        $rootNode->children()
            ->scalarNode('host')
            ->isRequired()
            ->cannotBeEmpty()
            ->end()
            ->scalarNode('username')
            ->isRequired()
            ->cannotBeEmpty()
            ->end()
            ->scalarNode('password')
            ->isRequired()
            ->cannotBeEmpty()
            ->end()
            ->booleanNode('bindRequiresDn')
            ->defaultTrue()
            ->end();

        return $treeBuilder;
    }

}