X-Git-Url: https://gerrit.simantics.org/r/gitweb?a=blobdiff_plain;f=bundles%2Forg.simantics.scl.runtime%2Fscl%2FPrelude.scl;h=907d6e00d74084dfc12dddedd205448624ecc2a8;hb=82a87b8535628d47d9c381e1a3a2296fb67c7fd0;hp=77e62c8582215cb6a4afcd3c4d65e26275bac0f1;hpb=de191b2614db104b4cd02d53a05c8896b10c4c90;p=simantics%2Fplatform.git

diff --git a/bundles/org.simantics.scl.runtime/scl/Prelude.scl b/bundles/org.simantics.scl.runtime/scl/Prelude.scl
index 77e62c858..907d6e00d 100644
--- a/bundles/org.simantics.scl.runtime/scl/Prelude.scl
+++ b/bundles/org.simantics.scl.runtime/scl/Prelude.scl
@@ -74,7 +74,7 @@ infixl 5  (\\), (<<), (<+)
 infix  4  (!=), (<), (<=), (>=), (>)
 infixr 3  (&&), (&<&)
 infixr 2  (||), orElse, morelse
-infixr 1  (>>=), (>>), (:=)
+infixr 1  (>>=), (>>), (:=), (>=>)
 infixr 1  ($)
 infixl 1  catch
 
@@ -921,6 +921,10 @@ Sequentially compose two actions, discarding any value produced by the first, li
 (>>) :: Monad m => m a -> m b -> m b
 a >> b = a >>= (\_ -> b)
 
+"Left-to-right Kleisli composition of monads."
+(>=>) :: Monad m => (a -> m b) -> (b -> m c) -> (a -> m c)
+(f >=> g) x = (f x) >>= g 
+
 "While loop. `while cond body` executes the `body` while the `cond` is true." 
 @inline
 while :: (<e> Boolean) -> (<e> a) -> <e> ()
@@ -1084,6 +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."