+ relative time jsont

src/json.ml

@@ -4,6 +4,8 @@ let encode_exn jsont v = Jsont_bytesrw.encode_string jsont v |> Result.get_ok
 let encode jsont v = Jsont_bytesrw.encode_string jsont v
 let decode jsont v = Jsont_bytesrw.decode_string jsont v
 
+(* JavaScript numbers restricted to integers. *)
+
 module Error_detail = struct
   open Error_detail
 
@@ -44,3 +46,31 @@ module Timestamp = struct
     |> Jsont.Object.mem "t_s" number_or_never_jsont ~enc:Fun.id
     |> Jsont.Object.finish
 end
+
+module Relative_time = struct
+  open Relative_time
+
+  let number_or_forever_jsont =
+    let forever =
+      let dec s =
+        match s with
+        | "forever" -> Forever
+        | _ -> Jsont.Error.msg Jsont.Meta.none "unexpected string value"
+      in
+      let enc = function Forever -> "forever" | _ -> assert false in
+      Jsont.map ~dec ~enc Jsont.string
+    in
+    let number =
+      let dec n = Microseconds n in
+      let enc = function Microseconds n -> n | _ -> assert false in
+      Jsont.map ~dec ~enc Jsont.number
+    in
+    let enc = function Forever -> forever | Microseconds _ -> number in
+    Jsont.any ~dec_string:forever ~dec_number:number ~enc ()
+
+  let jsont =
+    let make t_s = t_s in
+    Jsont.Object.map ~kind:"RelativeTime" make
+    |> Jsont.Object.mem "t_s" number_or_forever_jsont ~enc:Fun.id
+    |> Jsont.Object.finish
+end