Equipping extended maps with fold operator defined for any monad.

1 files changed, 14 insertions, 0 deletions

diff --git a/lib/hMap.ml b/lib/hMap.ml
index f902eded03..8e900cd581 100644
--- a/lib/hMap.ml
+++ b/lib/hMap.ml
@@ -329,4 +329,18 @@ struct
       Int.Map.map fs s
   end
 
+  module Monad(M : CMap.MonadS) =
+  struct
+    module IntM = Int.Map.Monad(M)
+    module ExtM = Map.Monad(M)
+    open M
+
+    let fold f s accu =
+      let ff _ m accu = ExtM.fold f m accu in
+      IntM.fold ff s accu
+
+    let fold_left _ _ _ = assert false
+    let fold_right _ _ _ = assert false
+  end
+
 end