X-Git-Url: https://gerrit.simantics.org/r/gitweb?a=blobdiff_plain;f=bundles%2Forg.simantics.scl.runtime%2Fscl%2FPrelude.scl;h=80b4d0ad794d8eca76d5210c5783fca6cba9a933;hb=8f1e3f237e21ecf19207ba1918041b0eefec4367;hp=751294a11bb44ea03df62391d7120c83bf9a1a0c;hpb=c52bf8a84f74dd22f49ca1c6e5443720c2d0ac3a;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 751294a11..80b4d0ad7 100644
--- a/bundles/org.simantics.scl.runtime/scl/Prelude.scl
+++ b/bundles/org.simantics.scl.runtime/scl/Prelude.scl
@@ -1290,8 +1290,13 @@ fromMaybe :: a -> Maybe a -> a
 fromMaybe default maybeValue = match maybeValue with
     Just v -> v
     _ -> default
-    
-    
+
+"`maybe def f v` returns `def` if `v=Nothing` and `f x` if `v=Just x`."
+@inline
+maybe :: b -> (a -> <e> b) -> Maybe a -> <e> b
+maybe n _ Nothing  = n
+maybe _ f (Just x) = f x
+
 """
 Provides a default value if the first parameter is Nothing.
 The default value is evaluated only if needed. The function