title: How to document a parameter that expects a constant
body: <p>What's the recommended way to document function or method parameters whose value is expected to be a predefined constant? So far, I use the data type of the constant and I add a little explanation later.</p>
  
  <p>E.g.:</p>
  
  <pre><code>&lt;?php
  
  class Foo{
      const METHOD_GET = 'get';
      const METHOD_POST = 'post';
  
      /**
       * Load a new foo
       *
       * @param string $method HTTP method to use (either Foo::METHOD_GET or Foo::METHOD_POST)
       */
      public function load($method=Foo::METHOD_POST){
          // ...
      }
  
      /**
       * Sort current foo
       *
       * @param int $sort_order Sort order (either SORT_ASC or SORT_DESC)
       */
      public function sort($sort_order=SORT_ASC){
          // ...
      }
  }
  </code></pre>