Sample of what modular serializer might look like

SerializerDecoratorSample.php

<?php

interface DecoratorInterface {
  public function dectorate($value, array $options);
  public function supports($class);
}

class InvalidDecoratorSerilizationException extends \Exception {};

class DateTimeDecorator impliments DecoratorInterface {
  public fuction decorate($value, array $options) {
    // Do something wih options
    if ($this->supports($value)) {
      return $value->format('c') . 'Z';
    }
    
    throw new InvalidDecoratorSerilizationException('Was unable to seri');
  }
  
  public function supports($class) {
    return $class instanceof \DateTime || is_subclass_of($class, \DateTime);
  }
}

class MarcoSerializer {
  private $availableDecorators = array();
  
  public __construct(array $decorators = array()) {
    $this->availableDecorators = array_merge($this->availableDecorators, $decorators);
  }
  
  public serialize($obj) {
    $serialized = array();
    foreach($obj as $key => $value) {
      // Key will be int for array.
      // ... do checks and balances
      
      $decorated = null;
      foreach($this->availableDecorators as $key => $decorator) {
        if ($decorator->supports($value)) {
          $decorated = $decorator->decorate($value);
        } else if ($value instanceof \Serializable) {
          $decorated = $value->serialize();
        } else {
          // Do fallback
        }
      }
      
      array_push($serialized, $decorated);
    }
    
    return json_encode($serialized);
  }
}