logict-state 0.1.0.4 → 0.1.0.5

raw patch · 3 files changed

+21/−21 lines, 3 filesPVP: major bump suggested

API removals or changes: PVP suggests a major version bump

API changes (from Hackage documentation)

Files

• logict-state.cabal +1/−1
• src/Control/Monad/LogicState.hs +8/−18
• src/Control/Monad/LogicState/Class.hs +12/−2

@@ -2,7 +2,7 @@ -- documentation, see http://haskell.org/cabal/users-guide/  name:                logict-state-version:             0.1.0.4+version:             0.1.0.5 synopsis:            Library for logic programming based on haskell package logict description:         Logic programming built on top of part of logict library, in particular for dealing with backtrackable state homepage:            https://github.com/atzedijkstra/logict-state

@@ -115,26 +115,11 @@  instance TransLogicState (gs,bs) (LogicStateT gs bs) where   observeT s lt = evalStateT (unLogicStateT lt (\a _ -> return a) (fail "No answer.")) s-  -  -- observeAllT s m = evalStateT (unLogicStateT m-  --   (\a fk -> fk >>= \as -> return (a:as))-  --   (return []))-  --   s-  +       observeStateAllT s m = runStateT (unLogicStateT m     (\a fk -> fk >>= \as -> return (a:as))     (return []))     s-  -  -- observeManyT s n m = evalStateT (obs n m) s-  --  where-  --    obs n m-  --       | n <= 0 = return []-  --       | n == 1 = unLogicStateT m (\a _ -> return [a]) (return [])-  --       | otherwise = unLogicStateT (msplit m) sk (return [])-  --    -  --    sk Nothing _ = return []-  --    sk (Just (a, m')) _ = StateT $ \s -> (\as -> (a:as,s)) `liftM` observeManyT s (n-1) m'    observeStateManyT s n m = runStateT (obs n m) s    where@@ -153,8 +138,13 @@     get   = LogicStateT $ \sk fk -> get >>= \s -> sk s fk     put s = LogicStateT $ \sk fk -> put s >>= \a -> sk a fk -instance (Monad m) => MonadLogicState (gs,bs) (LogicStateT gs bs m) where-    backtrack m = get >>= \(_::gs,bs) -> return $ LogicStateT $ \sk fk -> StateT $ \(gs,_) -> runStateT (unLogicStateT m sk fk) (gs,bs)+instance (Monad m) => MonadLogicState (,) gs bs m (LogicStateT gs bs m) where+    backtrackWithRoll roll m = do+      (_,bs1) <- get+      return $ LogicStateT $ \sk fk ->+        StateT $ \(gs2,bs2) -> do+          bs <- roll gs2 bs2 bs1+          runStateT (unLogicStateT m sk fk) (gs2,bs)   -------------------------------------------------------------------------

@@ -11,11 +11,21 @@  ------------------------------------------------------------------------------- -- | API for MonadLogic which allows state and backtracking on it.-class (MonadLogic m, MonadState s m) => MonadLogicState s m where+class (MonadLogic m, Monad ms, MonadState (f gs bs) m) => MonadLogicState f gs bs ms m | m -> ms where          -- | Return argument monad with the current backtrackable part of the state remembered.     -- If the default def is not overridden this a no-op.     -- This function complements 'mplus' for 'LogicT', 'mplus' backtracks on results, not on state, which is what this function should do.+    -- 'roll' accepts the end state of the backtrack attempt resp the state to backtrack to, returns to state to backtrack to.+    backtrackWithRoll+      :: (gs -> bs -> bs -> ms bs) -- ^ roll+      -> m a+      -> m (m a)+    backtrackWithRoll _ = backtrack+    +    -- | special case of 'backtrackWith'     backtrack :: m a -> m (m a)-    backtrack = return+    backtrack = backtrackWithRoll (\_ _ bs -> return bs)+    +