30 lines
1.0 KiB
OCaml
30 lines
1.0 KiB
OCaml
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type error = { code : Unix.error ; call : string ; parameter : string }
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type 'a t = ('a, error) Stdlib.Result.t
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module Operators = struct
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let ( let* ) (m : 'a t) (f : 'a -> 'b t) : 'b t = Stdlib.Result.bind m f
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let ( let+ ) (m : 'a t) (f : 'a -> 'b ) : 'b t = Stdlib.Result.map f m
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let ( ! ) (value : 'a) : 'a t = Stdlib.Result.Ok value
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end
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let return (value : 'a) : 'a t =
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Stdlib.Result.Ok value
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let error code call parameter : 'a t =
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Stdlib.Result.Error { code ; call ; parameter }
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let log { code ; call ; parameter } =
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Format.fprintf Format.err_formatter
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"@[<v>During the call %s(%s), the following error occured:@ - %s@ @]"
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call parameter (Unix.error_message code)
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let recover (io : 'a t) ~using ~on : 'a t =
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match io with
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| Ok result -> Ok result
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| Error e -> log e ; if e.code = on then using else Error e
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let environment_variable (variable : string) : string t =
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try Ok (Unix.getenv variable) with
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| Not_found -> error Unix.ENOENT "getenv" variable
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| Unix.Unix_error (code, call, param) -> error code call param
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