X-Git-Url: https://gerrit.simantics.org/r/gitweb?a=blobdiff_plain;f=bundles%2Forg.simantics.scl.db%2Fscl%2FSimantics%2FDB.scl;h=02396067875b83abb5c4fc25e44b4841bb7e47e6;hb=bb1507f;hp=ac50e3e73525dab3bd2f5afb71c59a0ab97800ed;hpb=6a4a43b278d6819c660182eb4954524d1757e077;p=simantics%2Fplatform.git

diff --git a/bundles/org.simantics.scl.db/scl/Simantics/DB.scl b/bundles/org.simantics.scl.db/scl/Simantics/DB.scl
index ac50e3e73..023960678 100644
--- a/bundles/org.simantics.scl.db/scl/Simantics/DB.scl
+++ b/bundles/org.simantics.scl.db/scl/Simantics/DB.scl
@@ -455,4 +455,28 @@ lift2Write f x y = syncWrite (\_ -> f x y)
 
 @inline
 lift3Write :: (a -> b -> c -> <WriteGraph,Proc> d) -> (a -> b -> c -> <Proc> d)
-lift3Write f x y z = syncWrite (\_ -> f x y z)
\ No newline at end of file
+lift3Write f x y z = syncWrite (\_ -> f x y z)
+
+"""
+Returns a child Browsable of the specified parent that has that is the child
+of the specified parent with the specified name path.
+"""
+childWithPath :: Browsable a => a -> [String] -> <ReadGraph> a
+childWithPath parent path = 
+    foldl (\r name -> match possibleChild r name with
+              Just c -> c
+              Nothing -> fail ("Didn't find " + name + ".") 
+          ) 
+          parent path
+
+"""
+Like `childWithPath` but returns Maybe a which will be `Nothing` if no child
+was found.
+"""
+possibleChildWithPath :: Browsable a => a -> [String] -> <ReadGraph> Maybe a
+possibleChildWithPath parent path = 
+    foldl (\r name -> match r with
+              Just c -> possibleChild c name
+              Nothing -> Nothing 
+          ) 
+          (Just parent) path