IfElse-0.85/0000755000076500000240000000000011124453303011406 5ustar jeffstaffIfElse-0.85/Control/0000755000076500000240000000000011124453303013026 5ustar jeffstaffIfElse-0.85/Control/Monad/0000755000076500000240000000000011124453303014064 5ustar jeffstaffIfElse-0.85/Control/Monad/IfElse.hs0000644000076500000240000001127211124453303015572 0ustar jeffstaff{-# LANGUAGE NoMonomorphismRestriction #-} -- | Library for control flow inside of monads with anaphoric variants on if and when and a C-like \"switch\" function. -- -- Information: -- -- [@Author@] Jeff Heard -- -- [@Copyright@] 2008 Jeff Heard -- -- [@License@] BSD -- -- [@Version@] 1.0 -- -- [@Status@] Alpha module Control.Monad.IfElse where import Control.Monad -- A if with no else for unit returning thunks. -- Returns the value of the test. -- when :: Monad m => Bool -> m () -> m Bool -- when True action = action >> return True -- when False _ = return False -- | A if with no else for unit returning thunks. -- Returns the value of the test. whenM :: Monad m => m Bool -> m () -> m () whenM test action = test >>= \t -> if t then action else return () -- | Like a switch statement, and less cluttered than if else if -- -- > cond [ (t1,a1), (t2,a2), ... ] cond :: Monad m => [(Bool, m ())] -> m () cond [] = return () cond ((True,action) : _) = action cond ((False,_) : rest) = cond rest -- | Like a switch statement, and less cluttered than if else if -- -- > condM [ (t1,a1), (t2,a2), ... ] condM :: Monad m => [(m Bool, m ())] -> m () condM [] = return () condM ((test,action) : rest) = test >>= \t -> if t then action else condM rest -- | Chainable anaphoric when. Takes a maybe value. -- -- if the value is Just x then execute @ action x @ , then return @ True @ . otherwise return @ False @ . awhen :: Monad m => Maybe a -> (a -> m ()) -> m () awhen Nothing _ = return () awhen (Just x) action = action x -- | Chainable anaphoric whenM. awhenM :: Monad m => m (Maybe a) -> (a -> m ()) -> m () awhenM test action = test >>= \t -> case t of Just x -> action x Nothing -> return () -- | Anaphoric when-else chain. Like a switch statement, but less cluttered acond :: Monad m => [(Maybe a, a -> m ())] -> m () acond ((Nothing,_) : rest) = acond rest acond ((Just x, action) : _) = action x acond [] = return () -- | Anaphoric if. aif :: Monad m => Maybe a -> (a -> m b) -> m b -> m b aif Nothing _ elseclause = elseclause aif (Just x) ifclause _ = ifclause x -- | Anaphoric if where the test is in Monad m. aifM :: Monad m => m (Maybe a) -> (a -> m b) -> m b -> m b aifM test ifclause elseclause = test >>= \t -> aif t ifclause elseclause -- | Contrapositive of whenM, if not x then do y unlessM a = whenM (liftM not $ a) -- | unless-else chain. ncond [] = return () ncond ((test , action) : rest) = if not test then action else ncond rest -- | monadic unless-else chain ncondM :: Monad m => [(m Bool, m ())] -> m () ncondM [] = return () ncondM ((test , action) : rest) = test >>= \t -> if not t then action else ncondM rest -- | IO lifted @ && @ (&&^) = liftM2 (&&) -- | IO lifted @ || @ (||^) = liftM2 (||) -- | Conditionally do the right action based on the truth value of the left expression (>>?) = when infixl 1 >>? -- | unless the left side is true, perform the right action (>>!) = unless infixl 1 >>! -- | unless the (monadic) left side is true, perform the right action (>>=>>!) = unlessM infixl 1 >>=>>! -- | Bind the result of the last expression in an anaphoric when. (>>=?) = awhen infixl 1 >>=? -- | composition of @ >>= @ and @ >>? @ (>>=>>?) = whenM infixl 1 >>=>>? -- | composition of @ >>= @ and @ >>=? @ (>>=>>=?) = awhenM infixl 1 >>=>>=? -- -- The following is from Control.Monad.Extras by Wren Thornton. -- -- | Execute a monadic action so long as a monadic boolean returns -- true. {-# SPECIALIZE whileM :: IO Bool -> IO () -> IO () #-} whileM :: (Monad m) => m Bool -> m () -> m () whileM mb m = do b <- mb ; when b (m >> whileM mb m) -- Named with M because 'Prelude.until' exists -- | Negation of 'whileM': execute an action so long as the boolean -- returns false. {-# SPECIALIZE untilM :: IO Bool -> IO () -> IO () #-} untilM :: (Monad m) => m Bool -> m () -> m () untilM mb m = do b <- mb ; unless b (m >> untilM mb m) -- | Strict version of 'return' because usually we don't need that -- extra thunk. {-# INLINE return' #-} return' :: (Monad m) => a -> m a return' x = return $! x -- | Take an action and make it into a side-effecting 'return'. -- Because I seem to keep running into @m ()@ and the like. infixr 8 `returning` {-# INLINE returning #-} returning :: (Monad m) => (a -> m b) -> (a -> m a) f `returning` x = f x >> return x -- For reference this is also helpful: -- > liftM2 (>>) f g == \x -> f x >> g x -- | This conversion is common enough to make a name for. {-# INLINE maybeMP #-} maybeMP :: (MonadPlus m) => Maybe a -> m a maybeMP = maybe mzero return -- This rule should only fire when type-safe {-# RULES "maybeMP/id" maybeMP = id #-} IfElse-0.85/IfElse.cabal0000644000076500000240000000067511124453303013551 0ustar jeffstaffName: IfElse Version: 0.85 Cabal-Version: >= 1.2 License: BSD3 License-File: LICENSE Author: J.R. Heard and Wren Thornton Maintainer: J.R. Heard Category: Control Description: Anaphoric and miscellaneous useful control-flow Synopsis: Anaphoric and miscellaneous useful control-flow Build-Type: Simple Library Build-Depends: base, mtl Exposed-Modules: Control.Monad.IfElse IfElse-0.85/LICENSE0000644000076500000240000000235011124453303012413 0ustar jeffstaffCopyright 2008, Jeff Heard. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. IfElse-0.85/Setup.hs0000644000076500000240000000005611124453303013043 0ustar jeffstaffimport Distribution.Simple main = defaultMain