> Well, if you consider large word-processors like word keep a complete > undo history, I > would keep a document as a list of changes: > > data Document = Insert Location String | Delete Location Location ...
Better to store it as a pair of the most recent state, and a list of *reversed* changes. --KW 8-) -- Keith Wansbrough <[EMAIL PROTECTED]> http://www.cl.cam.ac.uk/users/kw217/ University of Cambridge Computer Laboratory. _______________________________________________ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
