2013-05-22 ago explicit management of Session.Protocol_Handlers, with protocol state and functions;
2013-01-02 ago removed outdated comment;
2012-11-25 ago Isabelle-specific implementation of quasi-abstract markup elements -- back to module arrangement before d83797ef0d2d;
2012-09-20 ago more management of Invoke_Scala tasks;
2012-09-05 ago eliminated potentially confusing terminology of Scala "layer";
2012-03-03 ago clarified terminology of raw protocol messages;
2011-11-28 ago separate module for concrete Isabelle markup;
2011-08-19 ago Future.promise: explicit abort operation (like uninterruptible future job);
2011-07-11 ago tuned signature -- corresponding to Scala version;
2011-07-11 ago tuned signature;
2011-07-11 ago JVM method invocation service via Scala layer;