Initial commit of Python queries and QL libraries.

python/ql/src/Metrics/DocStringRatio.ql

@@ -0,0 +1,17 @@
+/**
+ * @name Percentage of docstrings
+ * @description The percentage of lines in a file that contain docstrings.
+ * @kind treemap
+ * @id py/doc-string-ratio-per-file
+ * @treemap.warnOn lowValues
+ * @metricType file
+ * @metricAggregate avg max
+ * @tags maintainability
+ *       documentation
+ */
+import python
+
+from Module m, ModuleMetrics mm
+where mm = m.getMetrics() and mm.getNumberOfLines() > 0 
+select m, 100.0 * ((float)mm.getNumberOfLinesOfDocStrings() / (float)mm.getNumberOfLines()) as ratio
+order by ratio desc