Added comments. Hooray!

1 files changed, 17 insertions, 0 deletions

diff --git a/extractor/vocabulary.h b/extractor/vocabulary.h
index 03c7dc66..c8fd9411 100644
--- a/extractor/vocabulary.h
+++ b/extractor/vocabulary.h
@@ -9,16 +9,33 @@ using namespace std;
 
 namespace extractor {
 
+/**
+ * Data structure for mapping words to word ids.
+ *
+ * This strucure contains words located in the frequent collocations and words
+ * encountered during the grammar extraction time. This dictionary is
+ * considerably smaller than the dictionaries in the data arrays (and so is the
+ * query time). Note that this is the single data structure that changes state
+ * and needs to have thread safe read/write operations.
+ *
+ * Note: For an experiment using different vocabulary instances for each thread,
+ * the running time did not improve implying that the critical regions do not
+ * cause bottlenecks.
+ */
 class Vocabulary {
  public:
   virtual ~Vocabulary();
 
+  // Returns the word id for the given word.
   virtual int GetTerminalIndex(const string& word);
 
+  // Returns the id for a nonterminal located at the given position in a phrase.
   int GetNonterminalIndex(int position);
 
+  // Checks if a symbol is a nonterminal.
   bool IsTerminal(int symbol);
 
+  // Returns the word corresponding to the given word id.
   virtual string GetTerminalValue(int symbol);
 
  private: