Small fix

ocaml/Circuits.ml

@@ -28,10 +28,11 @@ let get_inputs circ node =
 let get_op circ node =
   let (_, op) = get_node_info circ node in op
 
+(* extracts the two first inputs in a list of inputs *)
 let extract_bin_ins = function
   | [] -> failwith "Error extract_bin_ins: no input."
   | h1::h2::t -> (h1, h2)
-  | _ -> failwith "Error extract_bin_ins: inputs does not match."
+  | _ -> failwith "Error extract_bin_ins: inputs do not match."
 
 (* _________ Evaluation _________ *)
 
@@ -60,8 +61,8 @@ let rec value circ concl =
 
 let rec eval (circ : circuit) : int =
   let (_, _, concl) =
-    List.hd (List.filter (fun (_, o, _) -> o = COut) circ) in
-  value circ concl
+    List.hd (List.filter (fun (_, o, _) -> o = COut) circ)
+  in value circ concl
 
 (* _________ Examples _________ *)