Safe Haskell | None |
---|---|
Language | Haskell2010 |
- registerUndo :: TransientIO a -> TransientIO a
- onUndo :: TransientIO a -> TransientIO a -> TransientIO a
- undo :: TransientIO a
- retry :: TransIO ()
- undoCut :: TransientIO ()
Documentation
registerUndo :: TransientIO a -> TransientIO a Source #
register an action that will be executed when backtracking
onUndo :: TransientIO a -> TransientIO a -> TransientIO a Source #
the secod parameter will be executed when backtracking
undo :: TransientIO a Source #
execute backtracking. It execute the registered actions in reverse order.
If the backtracking flag is changed the flow proceed forward from that point on.
If the backtrack stack is finished or undoCut executed, undo
will stop.
undoCut :: TransientIO () Source #
assures that backtracking will not go further back