undo and marked linebreaks in text-widget

[Basim]

hi,

i have two questions concerning the tk(inter) text-widget:

1) are there any ready to use extensions which provide a 
undo/redo-mechanism? if not, what would be the best strategy? Would it be 
enough to override the widget's insert and delete-method and record these 
actions? (in my app there are no marks/bindings which have to be preserved)

2) could anyone point me the direction for extending the widget that 
line-breaks are marked by a special symbol?

thanks in advance,
Basim