Add some doc to EvaluateTreebank

Author: AngledLuffa

src/edu/stanford/nlp/parser/metrics/EvaluateTreebank.java

@@ -648,6 +648,12 @@ public void summarize(PrintWriter pwErr, TreebankLanguagePack tlp) {
     }
   }
 
+  /**
+   * Wrapper for a dataset which was already parsed, such as that passed in to EvaluateExternalParser.
+   * <br>
+   * Using this and the EvaluationDataset in general allows for scoring already known results and
+   * the results of a parser on raw text with the same codepaths
+   */
   public static class PreparsedEvaluationDataset implements EvaluationDataset {
     List<Pair<ParserQuery, Tree>> testTreebank;
 
@@ -729,6 +735,7 @@ public double testOnTreebank(EvaluationDataset testTreebank) {
       pwStats = null;
     }
 
+    System.err.println(testTreebank.getClass());
     testTreebank.processDataset(pwEvalErr, pwOut, pwFileOut, pwStats, treePrint,
                                 (pq, goldTree) -> processResults(pq, goldTree, pwEvalErr, pwOut, pwFileOut, pwStats, treePrint));