Source file monad.ml

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module Make (Trace : Traced_sigs.Trace.S) :
  Traced_sigs.Monad.S with type 'error trace = 'error Trace.trace = struct
  include Bare_structs.Monad

  type 'error trace = 'error Trace.trace

  module Traced_result_syntax = struct
    include Result_syntax

    let (fail[@ocaml.inline "always"]) = fun e -> fail (Trace.make e)

    let rec join_errors trace_acc = function
      | Ok _ :: ts -> join_errors trace_acc ts
      | Error trace :: ts -> join_errors (Trace.conp trace_acc trace) ts
      | [] -> Error trace_acc

    let rec join = function
      | [] -> Result_syntax.return_unit
      | Ok () :: ts -> join ts
      | Error trace :: ts -> join_errors trace ts

    let all ts =
      let rec aux acc = function
        | [] -> Ok (Stdlib.List.rev acc)
        | Ok v :: ts -> aux (v :: acc) ts
        | Error trace :: ts -> join_errors trace ts
      in
      aux [] ts

    let both a b =
      match (a, b) with
      | (Ok a, Ok b) -> Ok (a, b)
      | (Error err, Ok _) | (Ok _, Error err) -> Error err
      | (Error erra, Error errb) -> Error (Trace.conp erra errb)

    let ( and* ) = both

    let ( and+ ) = both
  end

  module Lwt_traced_result_syntax = struct
    include Lwt_result_syntax

    let (fail[@ocaml.inline "always"]) = fun e -> fail (Trace.make e)

    let join ts =
      let open Lwt_syntax in
      let+ ps = all ts in
      Traced_result_syntax.join ps

    let all ts =
      let open Lwt_syntax in
      let+ ps = all ts in
      Traced_result_syntax.all ps

    let both a b =
      let open Lwt_syntax in
      let+ (a, b) = both a b in
      Traced_result_syntax.both a b

    let ( and* ) = both

    let ( and+ ) = both
  end
end