decoding-variants#complex-variants

[idkjs]

Hi folks, tried to run this example complex-variants

module R =
  Decode.ParseError.ResultOf({
    type t = [ Decode.ParseError.base | `InvalidColor | `InvalidShape];
    let handle = x => (x :> t);
  });

module D = Decode.Base.Make(R.TransformError, R);
type color = Blue | Red | Green;

let parseColor =
  fun
  | "Blue" => Ok(Blue)
  | "Red" => Ok(Red)
  | "Green" => Ok(Green)
  | str => Error(Decode.ParseError.Val(`InvalidColor, Js.Json.string(str)));

let decodeColor = json => D.string |> Relude.Result.flatMap(parseColor);

Got the following error:

/DecodingVariantsComplex.re 18:39-71
  
  16 │   | str => Error(Decode.ParseError.Val(`InvalidColor, Js.Json.string(s
       tr)));
  17 │ 
  18 │ let decodeColor = json => D.string |> Relude.Result.flatMap(parseColor
       );
  
  This value might need to be wrapped in a function that takes an extra
  parameter of type Js.Json.t
  
  Here's the original error message
  This has type:
    Relude.Result.t(string, Decode.ParseError.t(([> `InvalidColor ] as 'a))) =>
    Relude.Result.t(color, Decode.ParseError.t('a))
  But somewhere wanted:
    (Js.Json.t => R.t(Js.String.t)) => 'b
  
  The incompatible parts:
    Relude.Result.t(string, Decode.ParseError.t('a)) (defined as
      Belt_Result.t(string, Decode.ParseError.t('a)))
    vs
    Js.Json.t => R.t(Js.String.t)
  
FAILED: subcommand failed.
>>>> Finish compiling(exit: 1)

Tried digging into the source but i am missing something. Thank you sir.

[mlms13]

Oops, looks like a typo in the example... that json argument should probably be fed into the actual decoder. :) Try let decodeColor = json => D.string(json) |> Relude.Result.flatMap(parseColor); and if that works, I'll update the example.

Too bad we don't have typechecking for the examples to make sure this stuff works :P

[idkjs]

Worked. Thank you, sir.

I hear it on the docs. A couple of spots need some linting. I will not be deterred!

[mlms13]

Reopening, just to make sure I don't forget to go update those docs. :D