add /F's PriorityQueue example

Doc/lib/libbisect.tex

@@ -61,7 +61,7 @@ The following functions are provided:
 \end{funcdesc}
 
 
-\subsection{Example}
+\subsection{Examples}
 \nodename{bisect-example}
 
 The \function{bisect()} function is generally useful for categorizing
@@ -81,3 +81,21 @@ breakpoints: 85 and up is an `A', 75..84 is a `B', etc.
 >>> map(grade, [33, 99, 77, 44, 12, 88])
 ['E', 'A', 'B', 'D', 'F', 'A']
 \end{verbatim}
+
+The bisect module can be used with the Queue module to implement a priority
+queue (example courtesy of Fredrik Lundh): \index{Priority Queue}
+
+\begin{verbatim}
+import Queue, bisect
+
+class PriorityQueue(Queue.Queue):
+    def _put(self, item):
+        bisect.insort(self.queue, item)
+
+# usage
+queue = PriorityQueue(0)
+queue.put((2, "second"))
+queue.put((1, "first"))
+queue.put((3, "third"))
+priority, value = queue.get()
+\end{verbatim}