X-Git-Url: https://gerrit.simantics.org/r/gitweb?a=blobdiff_plain;ds=sidebyside;f=bundles%2Forg.simantics.scl.runtime%2Fscl%2FMMap.scl;fp=bundles%2Forg.simantics.scl.runtime%2Fscl%2FMMap.scl;h=085728c5830d14db6f991dca5a0c4b7a623d69a4;hb=8cab2461c7f244ac8fabf2c7e61f0753dab68d00;hp=18e5866c080c05d35a6598c16e5382b63baa1a3f;hpb=ba07153e79390fea754342c51a1a669add711d95;p=simantics%2Fplatform.git

diff --git a/bundles/org.simantics.scl.runtime/scl/MMap.scl b/bundles/org.simantics.scl.runtime/scl/MMap.scl
index 18e5866c0..085728c58 100644
--- a/bundles/org.simantics.scl.runtime/scl/MMap.scl
+++ b/bundles/org.simantics.scl.runtime/scl/MMap.scl
@@ -35,6 +35,15 @@ importJava "java.util.Map" where
     remove :: T a b -> a -> <Proc> (Maybe b)
     clear :: T a b -> <Proc> ()
 
+@inline
+getOrCreate :: T a b -> (a -> <e> b) ->  a -> <Proc,e> b
+getOrCreate m f k = match get m k with
+    Just v -> v
+    Nothing -> do
+        v = f k
+        put m k v
+        v  
+
 @inline
 iter :: (a -> b -> <e> ()) -> T a b -> <e,Proc> ()
 iter f m = MSet.iter (\entry -> f (keyOf entry) (valueOf entry)) (entrySet m)