X-Git-Url: https://gerrit.simantics.org/r/gitweb?p=simantics%2Fplatform.git;a=blobdiff_plain;f=bundles%2Forg.simantics.scl.runtime%2Fscl%2FPrelude.scl;h=907d6e00d74084dfc12dddedd205448624ecc2a8;hp=05b5f2785675c6da8738e28287a465b6f8c22d4f;hb=82a87b8535628d47d9c381e1a3a2296fb67c7fd0;hpb=b4ad5dec5012b96765e6bb85f990500d2b376a96

diff --git a/bundles/org.simantics.scl.runtime/scl/Prelude.scl b/bundles/org.simantics.scl.runtime/scl/Prelude.scl
index 05b5f2785..907d6e00d 100644
--- a/bundles/org.simantics.scl.runtime/scl/Prelude.scl
+++ b/bundles/org.simantics.scl.runtime/scl/Prelude.scl
@@ -1088,6 +1088,22 @@ class (Functor f) => FunctorM f where
     sequence :: Monad m => f (m a) -> m (f a) 
     mapM f l = sequence (fmap f l)
 
+/// MonadE ///
+
+class (FunctorE m, Monad m) => MonadE m where
+    bindE :: m a -> (a -> <e> m b) -> <e> m b
+
+instance MonadE Maybe where
+    bindE Nothing  _ = Nothing
+    bindE (Just v) f = f v
+    
+instance MonadE (Either a) where
+    bindE (Left v)  _ = Left v
+    bindE (Right v) f = f v
+
+instance MonadE [] where
+    bindE l f = concatMap f l
+    
 /// Category ///
 
 "Identity function."