Add some primitives to make writing formatters easier

* ocaml_list
* quoted
* const
* record

src/import.ml

@@ -138,6 +138,29 @@ module Fmt = struct
   let nl = Format.pp_print_newline
 
   let prefix f g ppf x = f ppf; g ppf x
+
+  let ocaml_list pp fmt = function
+    | [] -> Format.pp_print_string fmt "[]"
+    | l ->
+      Format.fprintf fmt "@[<hv>[ %a@ ]@]"
+        (list ~pp_sep:(fun fmt () -> Format.fprintf fmt "@,; ")
+           pp) l
+
+  let quoted fmt = Format.fprintf fmt "%S"
+
+  let const
+    : 'a t -> 'a -> unit t
+    = fun pp a' fmt () -> pp fmt a'
+
+  let record fmt = function
+    | [] -> Format.pp_print_string fmt "{}"
+    | xs ->
+      let pp fmt (field, pp) =
+        Format.fprintf fmt "@[<hov 1>%s@ =@ %a@]"
+          field pp () in
+      let pp_sep fmt () = Format.fprintf fmt "@,; " in
+      Format.fprintf fmt "@[<hv>{ %a@ }@]"
+        (Format.pp_print_list ~pp_sep pp) xs
 end
 
 (* This is ugly *)