Safe Haskell | None |
---|---|
Language | Haskell2010 |
- registerUndo :: TransientIO a -> TransientIO a
- onUndo :: TransientIO a -> TransientIO a -> TransientIO a
- undo :: TransientIO a
- retry :: TransientIO ()
- 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.
retry :: TransientIO () Source
restart the flow forward from this point on
undoCut :: TransientIO () Source
assures that backtracking will not go further back