+ some type def

src/types.ml

@@ -17,3 +17,50 @@ module ErrorDetail = struct
   let to_string v = Jsont_bytesrw.encode_string jsont v |> Result.get_ok
   let of_string v = Jsont_bytesrw.decode_string jsont v
 end
+
+module Timestamp = struct
+  (* Seconds since epoch, or the special
+     value "never" to represent an event that will
+     never happen. *)
+  type t = Never | Seconds of int
+end
+
+module Amount = struct
+  (* Amounts of currency are always expressed in terms of a base value, a fractional value and the denomination of the currency.
+Amounts of currency are serialized as a string of the format <Currency>:<DecimalAmount>. Taler treats monetary amounts as fixed-precision numbers, with 8 decimal places. Unlike floating point numbers, this allows accurate representation of monetary amounts.
+
+The following constrains apply for a valid amount:
+    - <Currency> part must be at most 11 characters long and may only consist of ASCII letters (a-zA-Z).
+    - integer part of <DecimalAmount> may be at most 2^52.
+    - fractional part of <DecimalAmount> may contain at most 8 decimal digits.
+
+An amount that is prefixed with a + or - character is also used in certain contexts. When no sign is present, the amount is assumed to be positive. *)
+  type t = {
+      currency: [ `Eur ]
+    ; value: int
+    ; fraction: int
+    ; sign: [ `Plus | `Minus | `None ]
+  }
+end
+
+module Eddsa = struct
+  (* EdDSA and ECDHE public keys always point on Curve25519
+     and represented  using the standard 256 bits Ed25519 compact format,
+     converted to Crockford Base32. *)
+  type pub = string
+  type priv = string
+
+  (* EdDSA signatures are transmitted as 64-bytes base32
+   binary-encoded objects with just the R and S values (base32_ binary-only). *)
+  type signature = string
+end
+
+module Rsa = struct
+  (* RSA public key converted to Crockford Base32. *)
+  type pub = string
+end
+
+module Hash_code = struct
+  (* 32-byte value representing a point on Curve25519. *)
+  type cs25519Point = string
+end