Improve Mix.Local_bibliography

This modification even though a bit hacky, allows to choose your own
identifier for the bibliographic references. The `cite' function can
be called with an ?id optional argument to register use and it.  To be
then able to register an id without actually printing anything there
is the ?silent argument (hence then the id is registered when using
the `cites' function).

src/lib/dibrawi_mix.ml

@@ -211,29 +211,37 @@ module Make (Camlmix_input: CAMLMIX) = struct
   module Local_bibliography = struct
 
     let make ?pattern biblio =
-      let local_cites = (ref [] : (int * string) list ref) in
+      let local_cites = (ref [] : (int * string * string option) list ref) in
       let count = ref 0 in
-      let meta_cite f ref =
-        match Ls.find_opt !local_cites ~f:(fun (i, s) -> s = ref) with
-        | Some (i, s) -> f i
+      let meta_cite ?id f ref =
+        match Ls.find_opt !local_cites ~f:(fun (_, s, _) -> s = ref) with
+        | Some (i, s, None) -> f (string_of_int i)
+        | Some (i, s, Some id) -> f id
         | None -> 
           incr count;
-          local_cites := (!count, ref) :: !local_cites;
-          f !count
+          local_cites := (!count, ref, id) :: !local_cites;
+          match id with None -> f (string_of_int !count) | Some s -> f s
+      in
+      let cite ?(silent=false) ?id r =
+        meta_cite ?id (sprintf "[%s]") r |> 
+            (if not silent then pr else ignore)
       in
-      let cite = fun r -> meta_cite (sprintf "[%d]") r |> pr in
       let cites refs =
-        sprintf "[%s]" (Str.concat "," (Ls.map (meta_cite string_of_int) refs)) |> pr in
+        sprintf "[%s]" (Str.concat ", " 
+          (Ls.map (meta_cite (fun s -> s)) refs)) |> pr in
       let print () =
         let pattern_fun = 
           (match pattern with Some f -> f | None ->
-            sprintf "[%d] @{authors}; {i|@{title-punct}} @{how}, @{year}. {br}") in
-        Ls.iter (Ls.rev !local_cites) ~f:(fun (i, s) ->
+            sprintf "[%s] @{authors}; {i|@{title-punct}} @{how}, @{year}. {br}") in
+        Ls.iter (Ls.rev !local_cites) ~f:(fun (i, s, id) ->
           let subset = Sebib.Request.exec (`ids [s]) biblio in
           if Ls.length subset <> 1 then
             eprintf "Warning: subset has %d elements\n" (Ls.length subset);
-          let str = Sebib.Format.str ~pattern:(pattern_fun i) subset in
-          pr str) in
+          let str =
+            let idstr = match id with None -> string_of_int i | Some s -> s in
+            Sebib.Format.str ~pattern:(pattern_fun idstr) subset in
+          pr str;
+        ) in
       (cite, cites, print)
 
   end