Functional PHP: A getModule function that works like Node.js' require()

fancyApi.php

<?php

// I have no idea how to solve the problem of the fact that anything
// declared here ends up on the global scope.  Namespaces, maybe?  But
// I'm doing this in part to get away from namespaces and just let things
// be functional.  So I wrap it up in this load function but you should
// try to pick some name that won't conflict.

function fancyApi(&$exports) {
  $myConfig = 'World';

  // This fancy API simply prints a familiar message given the right inputs
  $exports['sayHello'] = function($hello) use ($myConfig) {
    echo "$hello, $myConfig!\n";
  };
}

fancyApi($exports);

?>

getModule.php

<?php
// This feels dirty

define('DS', '/');

// We have to initialize it with configuration.  Your software could just
// declare getModule as a non-anonymous function if you really wanted.
function createGetModule($basePath) {
  
  // We will store our loaded modules here.  Each call to createGetModule
  // gets its own module cache.  It's Functional Programming, and that's
  // how it goes.
  $loaded = array();
  
  // Return the actual getModule function
  return function($path) use ($loaded, $basePath) {
    
    // If a load hasn't happened before, we need to go do the actual load.
    if(!array_key_exists($path, $loaded)) {
      
      // Build the path - this could be configurable with more stuff passed
      // into the outer function createGetModule
      $file = $basePath . DS . $path . '.php';
      
      // Sanity checking because I like Exceptions better than Errors
      if(!file_exists($file)) throw new Exception($file . ' does not exist.');
      
      // The module just expects that this array will be available to it.
      // Everything the module exports will be put onto $exports.
      $exports = array();
      
      // Load the module in the PHP way
      require $file;
      
      // Cache the results.  Modules are singletons.
      $loaded[$path] = $exports;
    }
    
    // Return the result from cache
    return $loaded[$path];
  };

}
?>

index.php

#!/usr/bin/php
<?php

// We have to bootstrap things the old-fashioned way
require('getModule.php');

// Assign the getModule behavior to a variable.  Note that createGetModule returns a function.
$getModule = createGetModule(__DIR__);

// Use getModule to load fancyApi's exports
$api = $getModule('fancyApi');

echo "Here is what we get back:\n";
var_dump($api);

echo "\n\nAnd here is what happens if we run it:\n";
$api['sayHello']('Hello');

echo "\nUnfortunately, that function declared in fancyApi.php polluted the global scope:\nis_callable('fancyApi') = ";
var_dump(is_callable('fancyApi'));

?>