1 files changed, 12 insertions, 0 deletions
diff --git a/extractor/matchings_trie.h b/extractor/matchings_trie.h
index f3dcc075..1fb29693 100644
--- a/extractor/matchings_trie.h
+++ b/extractor/matchings_trie.h
@@ -11,20 +11,27 @@ using namespace std;
 
 namespace extractor {
 
+/**
+ * Trie node containing all the occurrences of the corresponding phrase in the
+ * source data.
+ */
 struct TrieNode {
   TrieNode(shared_ptr<TrieNode> suffix_link = shared_ptr<TrieNode>(),
            Phrase phrase = Phrase(),
            PhraseLocation matchings = PhraseLocation()) :
       suffix_link(suffix_link), phrase(phrase), matchings(matchings) {}
 
+  // Adds a trie node as a child of the current node.
   void AddChild(int key, shared_ptr<TrieNode> child_node) {
     children[key] = child_node;
   }
 
+  // Checks if a child exists for a given key.
   bool HasChild(int key) {
     return children.count(key);
   }
 
+  // Gets the child corresponding to the given key.
   shared_ptr<TrieNode> GetChild(int key) {
     return children[key];
   }
@@ -35,15 +42,20 @@ struct TrieNode {
   unordered_map<int, shared_ptr<TrieNode> > children;
 };
 
+/**
+ * Trie containing all the phrases that can be obtained from a sentence.
+ */
 class MatchingsTrie {
  public:
   MatchingsTrie();
 
   virtual ~MatchingsTrie();
 
+  // Returns the root of the trie.
   shared_ptr<TrieNode> GetRoot() const;
 
  private:
+  // Recursively deletes a subtree of the trie.
   void DeleteTree(shared_ptr<TrieNode> root);
 
   shared_ptr<TrieNode> root;