UTIL: add utility function for traceresult

Author: sipma

CodeHawk/CH/chutil/cHTraceResult.ml

@@ -87,6 +87,19 @@ let tbind ?(msg="") (f: 'a -> 'c traceresult) (r: 'a traceresult) =
   | Error e -> Error (msg :: e)
 
 
+let tbind2
+      ?(msg1="")
+      ?(msg2="")
+      (f: 'a -> 'b -> 'c traceresult)
+      (r1: 'a traceresult)
+      (r2: 'b traceresult): 'c traceresult =
+  match r1, r2 with
+  | Ok v1, Ok v2 -> f v1 v2
+  | Error e1, Ok _ -> Error (msg1 :: e1)
+  | Ok _, Error e2 -> Error (msg2 :: e2)
+  | Error e1, Error e2 -> Error (msg1 :: msg2 :: (e1 @ e2))
+
+
 let tfold ~(ok:'a -> 'c) ~(error:string list -> 'c) (r: 'a traceresult): 'c =
   match r with
   | Ok v -> ok v

CodeHawk/CH/chutil/cHTraceResult.mli

@@ -100,6 +100,15 @@ val tbind:
   ?msg:string -> ('a -> 'c traceresult) -> ('a traceresult) -> 'c traceresult
 
 
+val tbind2:
+  ?msg1:string
+  -> ?msg2:string
+  -> ('a -> 'b -> 'c traceresult)
+  -> 'a traceresult
+  -> 'b traceresult
+  -> 'c traceresult
+
+
 (** [titer ~ok ~error r] is [ok v] if [r] is [Ok v] and [error e] if [r] is
     [Error e].*)
 val titer: ok:('a -> unit) -> error:(string list -> unit) -> ('a traceresult) -> unit