added monadic file traversal helper

src/Convert/Traverse.hs

@@ -79,6 +79,7 @@ module Convert.Traverse
 , traverseScopesM
 , scopedConversion
 , stately
+, traverseFilesM
 , traverseFiles
 ) where
 
@@ -1068,17 +1069,25 @@ stately mapper thing = do
 -- packages, or typenames in other files. Global resolution of modules and
 -- interfaces is more commonly expected than global resolution of typenames and
 -- packages.
-traverseFiles
-    :: Monoid w
+traverseFilesM
+    :: (Monoid w, Monad m)
     => CollectorM (Writer w) AST
-    -> (w -> Mapper AST)
-    -> Mapper [AST]
-traverseFiles fileCollectorM fileMapper files =
-    map traverseFile files
+    -> (w -> MapperM m AST)
+    -> MapperM m [AST]
+traverseFilesM fileCollectorM fileMapperM files =
+    mapM traverseFileM files
     where
         globalNotes = execWriter $ mapM fileCollectorM files
-        traverseFile file =
-            fileMapper notes file
+        traverseFileM file =
+            fileMapperM notes file
             where
                 localNotes = execWriter $ fileCollectorM file
                 notes = localNotes <> globalNotes
+traverseFiles
+    :: Monoid w
+    => CollectorM (Writer w) AST
+    -> (w -> Mapper AST)
+    -> Mapper [AST]
+traverseFiles fileCollectorM fileMapper files =
+    evalState (traverseFilesM fileCollectorM fileMapperM  files) ()
+    where fileMapperM = (\w -> return . fileMapper w)