269 lines
8.3 KiB
OCaml
269 lines
8.3 KiB
OCaml
(**************************************************************************)
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(* *)
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(* Copyright (c) 2014 - 2016. *)
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(* Dynamic Ledger Solutions, Inc. <contact@tezos.com> *)
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(* *)
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(* All rights reserved. No warranty, explicit or implicit, provided. *)
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(* *)
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(**************************************************************************)
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module type QTY = sig
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val id : string
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end
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module type S = sig
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type qty
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type error +=
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| Addition_overflow of qty * qty (* `Temporary *)
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| Subtraction_underflow of qty * qty (* `Temporary *)
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| Multiplication_overflow of qty * int64 (* `Temporary *)
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| Negative_multiplicator of qty * int64 (* `Temporary *)
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| Invalid_divisor of qty * int64 (* `Temporary *)
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val id : string
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val zero : qty
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val one_cent : qty
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val fifty_cents : qty
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val one : qty
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val ( -? ) : qty -> qty -> qty tzresult
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val ( +? ) : qty -> qty -> qty tzresult
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val ( *? ) : qty -> int64 -> qty tzresult
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val ( /? ) : qty -> int64 -> qty tzresult
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val to_cents : qty -> int64
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(** [of_cents n] is None if n is negative *)
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val of_cents : int64 -> qty option
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(** [of_cents_exn n] fails if n is negative.
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It should only be used at toplevel for constants. *)
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val of_cents_exn : int64 -> qty
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(** It should only be used at toplevel for constants. *)
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val add_exn : qty -> qty -> qty
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val encoding : qty Data_encoding.t
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val to_int64 : qty -> int64
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include Compare.S with type t := qty
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val pp: Format.formatter -> qty -> unit
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val of_string: string -> qty option
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val to_string: qty -> string
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end
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module Make (T: QTY) : S = struct
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type qty = int64 (* invariant: positive *)
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type error +=
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| Addition_overflow of qty * qty (* `Temporary *)
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| Subtraction_underflow of qty * qty (* `Temporary *)
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| Multiplication_overflow of qty * int64 (* `Temporary *)
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| Negative_multiplicator of qty * int64 (* `Temporary *)
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| Invalid_divisor of qty * int64 (* `Temporary *)
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include Compare.Int64
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let zero = 0L
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let one_cent = 1L
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let fifty_cents = 50L
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let one = 100L
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let id = T.id
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let of_cents t =
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if t < 0L
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then None
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else Some t
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let of_string s =
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let len = String.length s in
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let rec dec i len acc =
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if Compare.Int.(i = len) then acc
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else
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dec (succ i) len
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(Int64.add (Int64.mul 10L acc)
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(match String.get s i with
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| '0' -> 0L | '1' -> 1L | '2' -> 2L | '3' -> 3L | '4' -> 4L
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| '5' -> 5L | '6' -> 6L | '7' -> 7L | '8' -> 8L | '9' -> 9L
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| _ -> raise Exit)) in
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let rec loop acc m len =
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if Compare.Int.(len >= 4) && Compare.Char.(String.get s (len - 4) = ',') then
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let acc = Int64.add acc Int64.(mul (dec (len - 3) len 0L) m) in
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loop acc Int64.(mul 1000L m) (len - 4)
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else
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Int64.add acc Int64.(mul (dec 0 len 0L) m) in
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let cents, len =
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if Compare.Int.(len >= 3) && Compare.Char.(String.get s (len - 3) = '.') then
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dec (len - 2) len 0L, len - 3
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else
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0L, len in
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let res =
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if Compare.Int.(len >= 4) && Compare.Char.(String.get s (len - 4) = ',') then
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loop cents 100L len
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else if Compare.Int.(len = 0) && Compare.Int.(String.length s = 3) then
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cents
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else
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try
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Int64.(add (mul 100L (of_string (String.sub s 0 len))) cents)
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with _ -> raise Exit in
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match of_cents res with
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| None -> raise Exit
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| Some tez -> tez
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let of_string s =
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try Some (of_string s) with Exit -> None
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let pp ppf amount =
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let rec loop ppf amount=
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let d, r = Int64.div amount 1000L, Int64.rem amount 1000L in
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if d > 0L then
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Format.fprintf ppf "%a,%03Ld" loop d r
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else
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Format.fprintf ppf "%Ld" r in
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let i, c = Int64.div amount 100L, Int64.rem amount 100L in
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Format.fprintf ppf "%a.%02Ld" loop i c
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let to_string t =
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Format.asprintf "%a" pp t
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let (-) t1 t2 =
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if t2 <= t1
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then Some (Int64.sub t1 t2)
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else None
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let (-?) t1 t2 =
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match t1 - t2 with
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| None -> error (Subtraction_underflow (t1, t2))
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| Some v -> ok v
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let (+?) t1 t2 =
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let t = Int64.add t1 t2 in
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if t < t1
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then error (Addition_overflow (t1, t2))
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else ok t
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let ( *? ) t m =
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let open Compare.Int64 in
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let open Int64 in
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let rec step cur pow acc =
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if cur = 0L then
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ok acc
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else
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pow +? pow >>? fun npow ->
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if logand cur 1L = 1L then
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acc +? pow >>? fun nacc ->
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step (shift_right_logical cur 1) npow nacc
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else
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step (shift_right_logical cur 1) npow acc in
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if m < 0L then
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error (Negative_multiplicator (t, m))
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else
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match step m t 0L with
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| Ok res -> Ok res
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| Error ([ Addition_overflow _ ] as errs) ->
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Error (Multiplication_overflow (t, m) :: errs)
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| Error errs -> Error errs
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let ( /? ) t d =
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if d <= 0L then
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error (Invalid_divisor (t, d))
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else
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ok (Int64.div t d)
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let add_exn t1 t2 =
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let t = Int64.add t1 t2 in
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if t <= 0L
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then invalid_arg "add_exn"
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else t
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let to_cents t = t
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let of_cents_exn x =
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match of_cents x with
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| None -> invalid_arg "Qty.of_cents"
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| Some v -> v
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let to_int64 t = t
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let encoding =
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let open Data_encoding in
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describe
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~title: "Amount in centiles"
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(conv to_int64 (Json.wrap_error of_cents_exn) int64)
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let () =
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let open Data_encoding in
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register_error_kind
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`Temporary
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~id:(T.id ^ ".addition_overflow")
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~title:("Overflowing " ^ T.id ^ " addition")
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~pp: (fun ppf (opa, opb) ->
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Format.fprintf ppf "Overflowing addition of %a %s and %a %s"
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pp opa T.id pp opb T.id)
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~description:
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("An addition of two " ^ T.id ^ " amounts overflowed")
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(obj1 (req "amounts" (tup2 encoding encoding)))
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(function Addition_overflow (a, b) -> Some (a, b) | _ -> None)
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(fun (a, b) -> Addition_overflow (a, b)) ;
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register_error_kind
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`Temporary
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~id:(T.id ^ ".subtraction_underflow")
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~title:("Underflowing " ^ T.id ^ " subtraction")
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~pp: (fun ppf (opa, opb) ->
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Format.fprintf ppf "Underflowing subtraction of %a %s and %a %s"
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pp opa T.id pp opb T.id)
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~description:
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("An subtraction of two " ^ T.id ^ " amounts underflowed")
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(obj1 (req "amounts" (tup2 encoding encoding)))
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(function Subtraction_underflow (a, b) -> Some (a, b) | _ -> None)
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(fun (a, b) -> Subtraction_underflow (a, b)) ;
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register_error_kind
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`Temporary
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~id:(T.id ^ ".multiplication_overflow")
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~title:("Overflowing " ^ T.id ^ " multiplication")
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~pp: (fun ppf (opa, opb) ->
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Format.fprintf ppf "Overflowing multiplication of %a %s and %Ld"
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pp opa T.id opb)
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~description:
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("A multiplication of a " ^ T.id ^ " amount by an integer overflowed")
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(obj2
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(req "amount" encoding)
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(req "multiplicator" int64))
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(function Multiplication_overflow (a, b) -> Some (a, b) | _ -> None)
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(fun (a, b) -> Multiplication_overflow (a, b)) ;
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register_error_kind
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`Temporary
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~id:(T.id ^ ".negative_multiplicator")
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~title:("Negative " ^ T.id ^ " multiplicator")
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~pp: (fun ppf (opa, opb) ->
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Format.fprintf ppf "Multiplication of %a %s by negative integer %Ld"
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pp opa T.id opb)
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~description:
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("Multiplication of a " ^ T.id ^ " amount by a negative integer")
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(obj2
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(req "amount" encoding)
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(req "multiplicator" int64))
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(function Negative_multiplicator (a, b) -> Some (a, b) | _ -> None)
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(fun (a, b) -> Negative_multiplicator (a, b)) ;
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register_error_kind
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`Temporary
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~id:(T.id ^ ".invalid_divisor")
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~title:("Invalid " ^ T.id ^ " divisor")
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~pp: (fun ppf (opa, opb) ->
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Format.fprintf ppf "Division of %a %s by non positive integer %Ld"
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pp opa T.id opb)
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~description:
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("Multiplication of a " ^ T.id ^ " amount by a non positive integer")
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(obj2
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(req "amount" encoding)
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(req "divisor" int64))
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(function Invalid_divisor (a, b) -> Some (a, b) | _ -> None)
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(fun (a, b) -> Invalid_divisor (a, b))
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end
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