From: Reino Ruusu <reino.ruusu@semantum.fi>
Date: Fri, 22 Mar 2019 12:51:03 +0000 (+0200)
Subject: Added effectful Kleisli composition to Prelude.
X-Git-Tag: v1.43.0~136^2~171^2
X-Git-Url: https://gerrit.simantics.org/r/gitweb?p=simantics%2Fplatform.git;a=commitdiff_plain;h=bd78deb4759a49ed84200b95fddc9569438512f7

Added effectful Kleisli composition to Prelude.

gitlab #280

Change-Id: If7a721ef2508b84490304a8353b31e8de9f25d27
---

diff --git a/bundles/org.simantics.scl.runtime/scl/Prelude.md b/bundles/org.simantics.scl.runtime/scl/Prelude.md
index df91f29d1..531a63587 100644
--- a/bundles/org.simantics.scl.runtime/scl/Prelude.md
+++ b/bundles/org.simantics.scl.runtime/scl/Prelude.md
@@ -81,13 +81,16 @@
 ## Monads
 
 ::class[Monad]
-::value[>>]
+::value[>>, >=>]
 ::class[FunctorM]
 ::value[repeatForever]
 ::class[MonadZero]
 ::value[guard]
 ::class[MonadPlus, MonadOr]
 ::value[ignoreM]
+::class[MonadE]
+::value[compE]
+::class[MonadZeroE]
 
 # Side-effects 
 
diff --git a/bundles/org.simantics.scl.runtime/scl/Prelude.scl b/bundles/org.simantics.scl.runtime/scl/Prelude.scl
index e92603bec..f98325109 100644
--- a/bundles/org.simantics.scl.runtime/scl/Prelude.scl
+++ b/bundles/org.simantics.scl.runtime/scl/Prelude.scl
@@ -1096,6 +1096,7 @@ class (FunctorE f) => FunctorM f where
 /// MonadE ///
 
 class (FunctorE m, Monad m) => MonadE m where
+    "An effectful version of the bind operator `(>>=)`"
     bindE :: m a -> (a -> <e> m b) -> <e> m b
 
 instance MonadE Maybe where
@@ -1109,6 +1110,11 @@ instance MonadE (Either a) where
 instance MonadE [] where
     bindE l f = concatMap f l
 
+@inline
+"An effectful version of the Kleisli composition operator `(>=>)`"
+compE :: MonadE m => (a -> <e> m b) -> (b -> <f> m c) -> a -> <e,f> m c
+compE f g x = (f x) `bindE` g
+
 /// MZeroE ///
 
 class (MonadE m, MonadZero m) => MonadZeroE m where