fun with symbols

Nothing at all on hackage is using <&&> or <||>.

(Also, <&&> should short-circuit on failure.)

Command/Find.hs

@@ -42,7 +42,7 @@ start :: Maybe Utility.Format.Format -> FilePath -> (Key, Backend) -> CommandSta
 start format file (key, _) = do
 	-- only files inAnnex are shown, unless the user has requested
 	-- others via a limit
-	whenM (orM limited (inAnnex key)) $
+	whenM (limited <||> inAnnex key) $
 		unlessM (showFullJSON vars) $
 			case format of
 				Nothing -> liftIO $ putStrLn file

Remote/Git.hs

@@ -7,8 +7,8 @@
 
 module Remote.Git (remote, repoAvail) where
 
-import Control.Exception.Extensible
 import qualified Data.Map as M
+import Control.Exception.Extensible
 
 import Common.Annex
 import Utility.CopyFile
@@ -102,11 +102,8 @@ tryGitConfigRead r
 	where
 		-- Reading config can fail due to IO error or
 		-- for other reasons; catch all possible exceptions.
-		safely a = do
+		safely a = either (const $ return r) return
-			result <- liftIO (try a :: IO (Either SomeException Git.Repo))
+				=<< liftIO (try a :: IO (Either SomeException Git.Repo))
-			case result of
-				Left _ -> return r
-				Right r' -> return r'
 
 		pipedconfig cmd params = safely $
 			pOpen ReadFromPipe cmd (toCommand params) $

Utility/Matcher.hs

@@ -78,8 +78,8 @@ match a m v = go m
 	where
 		go MAny = True
 		go (MAnd m1 m2) = go m1 && go m2
-		go (MOr m1 m2) = go m1 || go m2
+		go (MOr m1 m2) =  go m1 || go m2
-		go (MNot m1) = not (go m1)
+		go (MNot m1) = not $ go m1
 		go (MOp o) = a o v
 
 {- Runs a monadic Matcher, where Operations are actions in the monad. -}
@@ -87,8 +87,8 @@ matchM :: Monad m => Matcher (v -> m Bool) -> v -> m Bool
 matchM m v = go m
 	where
 		go MAny = return True
-		go (MAnd m1 m2) = andM (go m1) (go m2)
+		go (MAnd m1 m2) = go m1 <&&> go m2
-		go (MOr m1 m2) =  orM  (go m1) (go m2)
+		go (MOr m1 m2) =  go m1 <||> go m2
 		go (MNot m1) = liftM not (go m1)
 		go (MOp o) = o v
 

Utility/Monad.hs

@@ -8,7 +8,7 @@
 module Utility.Monad where
 
 import Data.Maybe
-import Control.Monad (liftM, liftM2)
+import Control.Monad (liftM)
 
 {- Return the first value from a list, if any, satisfying the given
  - predicate -}
@@ -31,15 +31,13 @@ ifM cond (thenclause, elseclause) = do
 	c <- cond
 	if c then thenclause else elseclause
 
-{- monadic ||
+{- short-circuiting monadic || -}
- -
+(<||>) :: Monad m => m Bool -> m Bool -> m Bool
- - Compare with (||) <$> ma <*> mb, which always runs both ma and mb. -}
+ma <||> mb = ifM ma ( return True , mb )
-orM :: Monad m => m Bool -> m Bool -> m Bool
-orM ma mb = ifM ma ( return True , mb )
 
-{- monadic &&  (for completeness) -}
+{- short-circuiting monadic && -}
-andM :: Monad m => m Bool -> m Bool -> m Bool
+(<&&>) :: Monad m => m Bool -> m Bool -> m Bool
-andM  = liftM2 (&&)
+ma <&&> mb = ifM ma ( mb , return False )
 
 {- Runs an action, passing its value to an observer before returning it. -}
 observe :: Monad m => (a -> m b) -> m a -> m a