Provides random undolist and undolist msg generators.
Generators
undolist:Int -> Int -> Generator state -> Generator (UndoList state)
Random UndoList Generator constructor.
Given a generator of state, a length for the past, and a length for the future,
generate a random undolist of states.
Random UndoList Generator constructor. Given a generator of state, a length for the past, and a length for the future, generate a random undolist of states.