X-Git-Url: https://gerrit.simantics.org/r/gitweb?a=blobdiff_plain;f=bundles%2Forg.simantics.scl.runtime%2Fscl%2FPrelude.scl;h=dc25349c8c04da7beab8d8b0d7d8df1187213381;hb=a472ceaa29534d553e2af893e268b6a13bffa441;hp=f983251093272d2168cb9eacc05db4542660afa0;hpb=278798fde2299d295af15addb3053d7101ccb17c;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 f98325109..dc25349c8 100644
--- a/bundles/org.simantics.scl.runtime/scl/Prelude.scl
+++ b/bundles/org.simantics.scl.runtime/scl/Prelude.scl
@@ -75,7 +75,7 @@ infixl 6  (+), (-)
 infixl 5  (\\), (<<), (<+)
 infix  4  (!=), (<), (<=), (>=), (>)
 infixr 3  (&&), (&<&)
-infixr 2  (||), orElse, morelse
+infixr 2  (||), orElse, orElseM, morelse
 infixr 1  (>>=), (>>), (:=), (>=>)
 infixr 1  ($)
 infixl 1  catch
@@ -2264,7 +2264,7 @@ importJava "java.lang.Throwable" where
     showThrowable :: Throwable -> String
     @private
     @JavaName getMessage 
-    getMessageThrowable :: Throwable -> String
+    getMessageThrowable :: Throwable -> Maybe String
     @private
     @JavaName getCause 
     getCauseThrowable :: Throwable -> Maybe Throwable
@@ -2283,7 +2283,12 @@ class Throwable e where
     toThrowable :: e -> Throwable
 
 messageOfException :: Throwable e => e -> String
-messageOfException = getMessageThrowable . toThrowable
+messageOfException e = match getMessageThrowable $ toThrowable e with
+                       Just m -> m
+                       Nothing -> ""
+                       
+possibleMessageOfException :: Throwable e => e -> Maybe String
+possibleMessageOfException e = getMessageThrowable $ toThrowable e
 
 causeOfException :: Throwable e => e -> Maybe Throwable
 causeOfException = getCauseThrowable . toThrowable