DI Container with configuration

Container.php

<?php

namespace MyNamespace;

/**
 * Dependency injection container
 */
class Container extends \Pimple\Container
{
    /**
     * Create a new container
     *
     * @param array $configuration Optional configuration to add to the Container.
     */
    public function __construct($configuration = null)
    {
        parent::__construct();

        // Path to a default configuration file.
        $this["CONFIGURATION_FILE"] = realpath(__DIR__ . "/../../../conf/config.php");

        // Apply an array to this container.
        $this["applyConfiguration"] = function ($c) {
            return function ($configuration) use ($c) {
                if ($configuration) {
                    foreach ($configuration as $key => $value) {
                        unset($c[$key]);
                        $c[$key] = $value;
                    };
                }
            };
        };

        // Include a file that returns an array and apply it to this contianer.
        $this["applyConfigurationFile"] = function ($c) {
            return function ($path) use ($c) {
                if (file_exists($path)) {
                    $configuration = include $path;
                    $c["applyConfiguration"]($configuration);
                }
            };
        };

        // Add the main stuff for your Container here.
        // At the end, call the


        ///////////////////
        // Configuration //
        ///////////////////

        // Add optional configuration passed to the constructor.
        $this["applyConfiguration"]($configuration);

        // Add the optional configuration file after the main keys have been added.
        $this["applyConfigurationFile"]($this["CONFIGURATION_FILE"]);
    }
}

show-config.php

#!/usr/bin/env php
<?php

use MyNamespace\Container;

require_once __DIR__ . "/../vendor/autoload.php";

$container = new Container();

$keys = $container->keys();
sort($keys);

foreach ($keys as $key) {
    $value = $container[$key];
    // NOTE: If you want to see strings wrapped in ", move the is_string check to the second part.
    if (is_numeric($value) || is_string($value)) {
        print "$key: $value\n";
    } elseif (is_bool($value) || is_array($value) || $value instanceof \stdClass) {
        print "$key: " . json_encode($value, JSON_PRETTY_PRINT) . "\n";
    }
}