Make the user_err header an optional parameter.

Suggested by @ppedrot

4 files changed, 18 insertions, 16 deletions

diff --git a/lib/cErrors.ml b/lib/cErrors.ml
index 830a9e3cea..38ed3f5ba7 100644
--- a/lib/cErrors.ml
+++ b/lib/cErrors.ml
@@ -33,12 +33,12 @@ let is_anomaly = function
 | Anomaly _ -> true
 | _ -> false
 
-exception UserError of string * std_ppcmds (* User errors *)
+exception UserError of string option * std_ppcmds (* User errors *)
 
 let todo s = prerr_string ("TODO: "^s^"\n")
 
-let user_err    ?loc s strm = Loc.raise ?loc (UserError (s,strm))
-let error            string = user_err "_" (str string)
+let user_err ?loc ?hdr strm = Loc.raise ?loc (UserError (hdr, strm))
+let error            string = user_err (str string)
 
 let invalid_arg ?loc s   = Loc.raise ?loc (Invalid_argument s)
 
@@ -112,7 +112,7 @@ let iprint_no_report (e, info) =
 
 let _ = register_handler begin function
   | UserError(s, pps) ->
-    hov 0 (str "Error: " ++ where (Some s) ++ pps)
+    hov 0 (str "Error: " ++ where s ++ pps)
   | _ -> raise Unhandled
 end
 
diff --git a/lib/cErrors.mli b/lib/cErrors.mli
index ad17be393f..5cffc725d9 100644
--- a/lib/cErrors.mli
+++ b/lib/cErrors.mli
@@ -33,11 +33,13 @@ val is_anomaly : exn -> bool
     This is mostly provided for compatibility. Please avoid doing specific
     tricks with anomalies thanks to it. See rather [noncritical] below. *)
 
-exception UserError of string * std_ppcmds
+exception UserError of string option * std_ppcmds
+(** Main error signaling exception. It carries a header plus a pretty printing
+    doc *)
 
-val user_err     : ?loc:Loc.t -> string -> std_ppcmds -> 'a
-(** Main error raising primitive. [user_err ?loc c pp] signals an
-    error [pp] in component [c], with optional location [loc] *)
+val user_err : ?loc:Loc.t -> ?hdr:string -> std_ppcmds -> 'a
+(** Main error raising primitive. [user_err ?loc ?hdr pp] signals an
+    error [pp] with optional header and location [hdr] [loc] *)
 
 val error : string -> 'a
 (** [error s] just calls [user_error "_" (str s)] *)
diff --git a/lib/cWarnings.ml b/lib/cWarnings.ml
index f36c7ad80d..18b26254db 100644
--- a/lib/cWarnings.ml
+++ b/lib/cWarnings.ml
@@ -45,7 +45,7 @@ let create ~name ~category ?(default=Enabled) pp =
            | Disabled -> ()
            | AsError ->
               let loc = Option.default !current_loc loc in
-              CErrors.user_err ~loc "_" (pp x)
+              CErrors.user_err ~loc (pp x)
            | Enabled ->
               let msg =
                 pp x ++ spc () ++ str "[" ++ str name ++ str "," ++
diff --git a/lib/system.ml b/lib/system.ml
index 916c087959..0f610b8d53 100644
--- a/lib/system.ml
+++ b/lib/system.ml
@@ -132,7 +132,7 @@ let find_file_in_path ?(warn=true) paths filename =
       let root = Filename.dirname filename in
       root, filename
     else
-      CErrors.user_err "System.find_file_in_path"
+      CErrors.user_err ~hdr:"System.find_file_in_path"
 	(hov 0 (str "Can't find file" ++ spc () ++ str filename))
   else
     (* the name is considered to be the transcription as a relative
@@ -140,7 +140,7 @@ let find_file_in_path ?(warn=true) paths filename =
        to be locate respecting case *)
     try where_in_path ~warn paths filename
     with Not_found ->
-      CErrors.user_err "System.find_file_in_path"
+      CErrors.user_err ~hdr:"System.find_file_in_path"
 	(hov 0 (str "Can't find file" ++ spc () ++ str filename ++ spc () ++
 		str "on loadpath"))
 
@@ -163,7 +163,7 @@ let is_in_system_path filename =
 let open_trapping_failure name =
   try open_out_bin name
   with e when CErrors.noncritical e ->
-    CErrors.user_err "System.open" (str "Can't open " ++ str name)
+    CErrors.user_err ~hdr:"System.open" (str "Can't open " ++ str name)
 
 let warn_cannot_remove_file =
   CWarnings.create ~name:"cannot-remove-file" ~category:"filesystem"
@@ -175,7 +175,7 @@ let try_remove filename =
     warn_cannot_remove_file filename
 
 let error_corrupted file s =
-  CErrors.user_err "System" (str file ++ str ": " ++ str s ++ str ". Try to rebuild it.")
+  CErrors.user_err ~hdr:"System" (str file ++ str ": " ++ str s ++ str ". Try to rebuild it.")
 
 let input_binary_int f ch =
   try input_binary_int ch
@@ -252,7 +252,7 @@ let extern_state magic filename val_0 =
       let () = try_remove filename in
       iraise reraise
   with Sys_error s ->
-    CErrors.user_err "System.extern_state" (str "System error: " ++ str s)
+    CErrors.user_err ~hdr:"System.extern_state" (str "System error: " ++ str s)
 
 let intern_state magic filename =
   try
@@ -261,12 +261,12 @@ let intern_state magic filename =
     close_in channel;
     v
   with Sys_error s ->
-    CErrors.user_err "System.intern_state" (str "System error: " ++ str s)
+    CErrors.user_err ~hdr:"System.intern_state" (str "System error: " ++ str s)
 
 let with_magic_number_check f a =
   try f a
   with Bad_magic_number {filename=fname;actual=actual;expected=expected} ->
-    CErrors.user_err "with_magic_number_check"
+    CErrors.user_err ~hdr:"with_magic_number_check"
     (str"File " ++ str fname ++ strbrk" has bad magic number " ++
     int actual ++ str" (expected " ++ int expected ++ str")." ++
     spc () ++