1 files changed, 45 insertions, 0 deletions
diff --git a/lib/concepts/Tuple.ml b/lib/concepts/Tuple.ml
new file mode 100644
index 0000000..296bf26
--- /dev/null
+++ b/lib/concepts/Tuple.ml
@@ -0,0 +1,45 @@
+type t = { type_ : string; attributes : Value.value BatMap.String.t }
+
+let malformed_value () =
+  Condition.condition "malformed-tuple-value"
+    "A tuple field did not conform to what was expected" Condition.empty
+
+let bencode_of_value = function
+  | Value.String s -> Encoding.Bencode.Tagged ('s', Encoding.Bencode.String s)
+  | Value.Integer n -> Encoding.Bencode.Tagged ('i', Encoding.Bencode.Int n)
+
+let value_of_bencode = function
+  | Encoding.Bencode.Tagged ('s', Encoding.Bencode.String s) -> Ok (Value.String s)
+  | Encoding.Bencode.Tagged ('i', Encoding.Bencode.Int n) -> Ok (Value.Integer n)
+  | _ -> Error (malformed_value ())
+
+module rec Representation : (Encoding.Record.S with type t = t) =
+  Encoding.Record.Make (Body)
+
+and Body : Encoding.Record.BODY = struct
+  type nonrec t = t
+
+  let tag = 'T'
+  let malformed = malformed_value
+
+  let fields { type_; attributes } =
+    [ "type", Encoding.Bencode.String type_;
+      "attributes",
+      Encoding.Bencode.Dict
+        (BatMap.String.enum attributes
+         |> BatEnum.fold
+              (fun acc (name, value) -> (name, bencode_of_value value) :: acc)
+              []) ]
+
+  let of_fields data =
+    let open Utilities.Result in
+    let* type_ = Encoding.Bencode.field "type" data |> fmap Encoding.Bencode.as_string in
+    let* kvs = Encoding.Bencode.field "attributes" data |> fmap Encoding.Bencode.as_dict in
+    kvs
+    |> List.map (fun (name, v) -> value_of_bencode v |> Result.map (fun v -> (name, v)))
+    |> Utilities.List.sequence
+    |> Result.map (fun kvs ->
+           { type_; attributes = BatMap.String.of_list kvs })
+end
+
+let hash tuple = Representation.to_blob tuple |> Hash.hash_of_blob