foo_validator.php

<?php

class FooValidator implements Validator
{
  public function __construct(Validator $validator)
  {
    $this->validator = $validator
    $this->validator->rule('name', 'not_empty')
              ->rule('name', 'max_length', [':value', 35])
              ->rule('name', 'min_length', [':value', 5]);
  }
  
  public function validate(array $values)
  {
    // do it here with values
  }
}

validator.php

<?php

interface Validator
{
  public function validate(array $values);
}