Re: Type error: `Eof isn't the same as `Eof ?

2014-09-09 10:42 UTC−07:00, [email protected] [ocaml_beginners] wrote:
> I have this code that tries to log the output of a pipe:
>
>
>    Async.Std.print_string (match (Async.Std.Pipe.read r) with
>                            | `Eof -> "an empty string"
>                            | `Ok text -> text)
>
>
>
>  However, I get this type error when compiling:
>
>
>  File "hello_world.ml", line 57, characters 29-33:
> Error: This pattern matches values of type [? `Eof ]
>        but a pattern was expected which matches values of type
>          [ `Eof | `Ok of string ] Async_conduit.io
>
>
>
>  Should I qualify these `Eof and `Ok somehow?
>
>
>
>  What I am trying to do is to log the content of the body of a POST request.
> The body content is to be salvaged through a pipe.
>
>
>  The full code can be seen here:
>
> https://github.com/loldrup/ocaml-cohttp/blob/master/examples/async/hello_world.ml

If I look at the documentation online for the function Async.Std.Pipe.read:

https://ocaml.janestreet.com/ocaml-core/111.28.00/doc/async/#Std.Pipe

I see that its signature is:
val read : ?consumer:Consumer.t -> 'a Reader.t -> [ `Eof | `Ok of 'a ]
Deferred.t

Indeed the returned type is not [ `Eof | `Ok of 'a ] , the API of
asunc probably changed since this hello-world was written.

So either you raise an issue on the github page of ocaml-cohttp,
either you send them a patch.

Florent