Add a functor to help define errors

Signed-off-by: Jon Ludlam <[email protected]>
jonludlam · Nov 23, 2016 · 1b5e412 · 1b5e412
1 parent 54f38ef
commit 1b5e412
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Showing 3 changed files with 16 additions and 6 deletions.
diff --git a/example/example3_idl.ml b/example/example3_idl.ml
@@ -36,13 +36,9 @@ type blocklist = {
 type error =
   | Unimplemented of string
   [@@deriving rpcty]
-exception Exn of error
 
-let error = Idl.Error.{
-    def=error;
-    raiser=(fun e -> raise (Exn e));
-    matcher=(function | Exn e -> Some e | _ -> None);
-  }
+module E = Idl.Error.Make(struct type t=error let t = error end)
+let error = E.error
 
 type domain = string
   [@@deriving rpcty]

diff --git a/lib/idl.ml b/lib/idl.ml
@@ -22,6 +22,16 @@ module Error = struct
     raiser : 'a -> exn;
     matcher : exn -> 'a option;
   }
+
+  module Make(T : sig type t val t : t Rpc.Types.def end) = struct
+    exception Exn of T.t
+    let error = {
+        def = T.t;
+        raiser = (function e -> Exn e);
+        matcher = (function | Exn e -> Some e | _ -> None)
+      }
+  end
+
 end
 
 module Interface = struct

diff --git a/lib/idl.mli b/lib/idl.mli
@@ -29,6 +29,10 @@ module Error : sig
     raiser : 'a -> exn;
     matcher : exn -> 'a option;
   }
+
+  module Make(T : sig type t val t : t Rpc.Types.def end) : sig
+    val error : T.t t
+  end
 end
 
 (** An interface is a collection of RPC declarations. *)