3 files changed, 25 insertions, 2 deletions
diff --git a/src/compiler/GF/Data/BacktrackM.hs b/src/compiler/GF/Data/BacktrackM.hs
index 4e84022f4..f5ae63997 100644
--- a/src/compiler/GF/Data/BacktrackM.hs
+++ b/src/compiler/GF/Data/BacktrackM.hs
@@ -29,6 +29,7 @@ module GF.Data.BacktrackM (
 		  ) where
 
 import Data.List
+import Control.Applicative
 import Control.Monad
 import Control.Monad.State.Class
 
@@ -60,6 +61,10 @@ foldFinalStates f b (BM m) s = m (\x s b -> f s b) s b
 finalStates :: BacktrackM s () -> s -> [s]
 finalStates bm = map fst . runBM bm
 
+instance Applicative (BacktrackM s) where
+    pure = return
+    (<*>) = ap
+
 instance Monad (BacktrackM s) where
     return a   = BM (\c s b -> c a s b)
     BM m >>= k = BM (\c s b -> m (\a s b -> unBM (k a) c s b) s b)
@@ -69,6 +74,10 @@ instance Monad (BacktrackM s) where
 instance Functor (BacktrackM s) where
     fmap f (BM m) = BM (\c s b -> m (\a s b -> c (f a) s b) s b)
 
+instance Alternative (BacktrackM s) where
+   empty = mzero
+   (<|>) = mplus
+
 instance MonadPlus (BacktrackM s) where
     mzero                 = BM (\c s b -> b)
     (BM f) `mplus` (BM g) = BM (\c s b -> g c s $! f c s b)
diff --git a/src/compiler/GF/Data/ErrM.hs b/src/compiler/GF/Data/ErrM.hs
index e8cea12d4..d687a70a5 100644
--- a/src/compiler/GF/Data/ErrM.hs
+++ b/src/compiler/GF/Data/ErrM.hs
@@ -14,7 +14,8 @@
 
 module GF.Data.ErrM (Err(..)) where
 
-import Control.Monad (MonadPlus(..))
+import Control.Monad (MonadPlus(..),ap)
+import Control.Applicative
 
 -- | like @Maybe@ type with error msgs
 data Err a = Ok a | Bad String
@@ -31,8 +32,16 @@ instance Functor Err where
   fmap f (Ok a) = Ok (f a)
   fmap f (Bad s) = Bad s
 
+instance Applicative Err where
+  pure = return
+  (<*>) = ap
+
 -- | added by KJ
 instance MonadPlus Err where
     mzero = Bad "error (no reason given)"
     mplus (Ok a)  _ = Ok a
     mplus (Bad s) b = b
+
+instance Alternative Err where
+    empty = mzero
+    (<|>) = mplus
diff --git a/src/compiler/GF/Data/Operations.hs b/src/compiler/GF/Data/Operations.hs
index cd42156d4..ef34de27b 100644
--- a/src/compiler/GF/Data/Operations.hs
+++ b/src/compiler/GF/Data/Operations.hs
@@ -67,7 +67,8 @@ import Data.Char (isSpace, toUpper, isSpace, isDigit)
 import Data.List (nub, partition, (\\))
 import qualified Data.Map as Map
 import Data.Map (Map)
-import Control.Monad (liftM,liftM2)
+import Control.Applicative(Applicative(..))
+import Control.Monad (liftM,liftM2,ap)
 
 import GF.Data.ErrM
 import GF.Data.Relation
@@ -330,6 +331,10 @@ stmr f = stm (\s -> return (f s))
 
 instance Functor (STM s) where fmap = liftM
 
+instance Applicative (STM s) where
+  pure = return
+  (<*>) = ap
+
 instance  Monad (STM s) where
   return a    = STM (\s -> return (a,s))
   STM c >>= f = STM (\s -> do