code: public Iterator<IntTaggedWord> ruleIteratorByWord(String word, int loc) {
      return ruleIteratorByWord(wordIndex.indexOf(word, true), loc, null);
    }
docs: Returns the possible POS taggings for a word.
  
  @param word The word, represented as an integer in wordIndex
  @param loc  The position of the word in the sentence (counting from 0).
  <i>Implementation note: The BaseLexicon class doesn't actually
  make use of this position information.</i>
  @return An Iterator over a List ofIntTaggedWords, which pair the word with
  possible taggings as integer pairs. (Each can be thought of as a
  <code>tag -&gt; word<code> rule.)