Fix #5437: when registering an option with Arg, if the option has an empty doc string, do not include it when printing the usage.

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@11939 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02

Changes

@@ -35,6 +35,8 @@ Standard library:
     . Added optional "seed" parameter to Hashtbl.create for diversification
     . Added new functorial interface "MakeSeeded" to support diversification
       with user-provided hash functions.
+- Arg: options with empty doc strings are no longer included in the usage string
+  (PR#5437)
 
 Bug Fixes:
 - PR#4869: rare collisions between assembly labels for code and data

stdlib/arg.ml

@@ -64,10 +64,11 @@ let make_symlist prefix sep suffix l =
 ;;
 
 let print_spec buf (key, spec, doc) =
-  match spec with
-  | Symbol (l, _) -> bprintf buf "  %s %s%s\n" key (make_symlist "{" "|" "}" l)
-                             doc
-  | _ -> bprintf buf "  %s %s\n" key doc
+  if String.length doc > 0 then
+    match spec with
+    | Symbol (l, _) -> bprintf buf "  %s %s%s\n" key (make_symlist "{" "|" "}" l)
+                               doc
+    | _ -> bprintf buf "  %s %s\n" key doc
 ;;
 
 let help_action () = raise (Stop (Unknown "-help"));;

stdlib/arg.mli

@@ -83,6 +83,8 @@ val parse :
 -   The reason for the error: unknown option, invalid or missing argument, etc.
 -   [usage_msg]
 -   The list of options, each followed by the corresponding [doc] string.
+    Beware: options that have an empty [doc] string will not be included in the
+    list.
 
     For the user to be able to specify anonymous arguments starting with a
     [-], include for example [("-", String anon_fun, doc)] in [speclist].