UMLGraph allows the declarative specification and drawing of UML class and sequence diagrams.

The following is an example of a sequence diagram specification and the resulting UML diagram:

Define the objects object(O,"o:Toolkit"); placeholder_object(P); step(); # Activation and messages active(O); message(O,O,"callbackLoop()"); create_message(O,P,"p:Peer"); message(O,P,"handleExpose()"); active(P); return_message(P,O,""); inactive(P); destroy_message(O,P); inactive(O); # Complete the lifeline of O step(); complete(O);