Clean and fix definitions of options.

- Provide new helper functions in `Goptions` on the model of
  `declare_bool_option_and_ref`;

- Use these helper functions in many parts of the code base
  (encapsulates the corresponding references);

- Move almost all options from `declare_string_option` to
  `declare_stringopt_option` (only "Warnings" continue to use the
  former).  This means that these options now support `Unset` to get
  back to the default setting.  Note that there is a naming
  misalignment since `declare_int_option` is similar to
  `declare_stringopt_option` and supports `Unset`.  When "Warning" is
  eventually migrated to support `Unset` as well, we can remove
  `declare_string_option` and rename `declare_stringopt_option` to
  `declare_string_option`.

- For some vernac options and flags that have an equivalent
  command-line option or flag, implement it like the standard `-set`
  and `-unset`.

1 files changed, 3 insertions, 9 deletions

diff --git a/plugins/ltac/g_ltac.mlg b/plugins/ltac/g_ltac.mlg
index 50c3ed1248..2bd4211c90 100644
--- a/plugins/ltac/g_ltac.mlg
+++ b/plugins/ltac/g_ltac.mlg
@@ -359,21 +359,15 @@ open Vernacextend
 open Goptions
 open Libnames
 
-let print_info_trace = ref None
-
-let () = declare_int_option {
-  optdepr = false;
-  optkey = ["Info" ; "Level"];
-  optread = (fun () -> !print_info_trace);
-  optwrite = fun n -> print_info_trace := n;
-}
+let print_info_trace =
+  declare_intopt_option_and_ref ~depr:false ~key:["Info" ; "Level"]
 
 let vernac_solve ~pstate n info tcom b =
   let open Goal_select in
   let pstate, status = Proof_global.map_fold_proof_endline (fun etac p ->
       let with_end_tac = if b then Some etac else None in
       let global = match n with SelectAll | SelectList _ -> true | _ -> false in
-      let info = Option.append info !print_info_trace in
+      let info = Option.append info (print_info_trace ()) in
       let (p,status) =
         Pfedit.solve n info (Tacinterp.hide_interp global tcom None) ?with_end_tac p
       in