Add documentation

Author: clue

src/Directed.php

@@ -5,11 +5,29 @@
 use Fhaculty\Graph\Set;
 use Fhaculty\Graph\Algorithm\Base;
 use Fhaculty\Graph\Edge\Directed as EdgeDirected;
+use Fhaculty\Graph\Graph;
+use Fhaculty\Graph\Walk;
 
+/**
+ * Basic algorithms for working with the undirected or directed Graphs (digraphs) / Walks.
+ *
+ * @link http://en.wikipedia.org/wiki/Glossary_of_graph_theory#Direction
+ * @link http://en.wikipedia.org/wiki/Digraph_%28mathematics%29
+ */
 class Directed extends Base
 {
+    /**
+     * Graph/Walk to operate on
+     *
+     * @var Set
+     */
     private $set;
 
+    /**
+     * instanciate new directed algorithm
+     *
+     * @param Set|Graph|Walk $graphOrWalk either the Graph or Walk to operate on (or the common base class Set)
+     */
     public function __construct(Set $graphOrWalk)
     {
         $this->set = $graphOrWalk;