PaLy/alg-vis — comment on commit 0fd6e063855e1c595fd76321c91191068ca90214
File: src/algvis/core/Scenario.java line 18
By kuk0:

so actually, the history doesn't have to be an XML document... you can have several classes that will store commands such as "move", "change color", or "pause" and the scenario could export the history in XML format
so Scenario is a list of Commands (Command is an abstract class with several subclasses; each can do and undo the action and return the xml code)