diff options
Diffstat (limited to 'AAC_search_monad.ml')
| -rw-r--r-- | AAC_search_monad.ml | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/AAC_search_monad.ml b/AAC_search_monad.ml index b7aabbd..09a6455 100644 --- a/AAC_search_monad.ml +++ b/AAC_search_monad.ml @@ -63,3 +63,8 @@ let to_list m = (fold (fun x acc -> x::acc) m []) let sort f m = N (List.map (fun x -> F x) (List.sort f (to_list m))) + +(* preserve the structure of the heap *) +let filter f m = + fold (fun x acc -> (if f x then return x else fail ()) >>| acc) m (N []) + |