Re: [Caml-list] do i need a private row type?

[Joel Reymont <joelr1@gmail.com>]

Here's the problem reduced to a single file. 

Two files, actually, the first one showing my intended use.

The error is 

File "zmq.ml", line 72, characters 7-86:
Error: A type variable is unbound in this type declaration.
In type
  ([< `Dealer | `Pair | `Pub | `Pull | `Push | `Rep | `Req | `Router | `Sub ]
   as 'a)
  Socket.t the variable 'a is unbound

	Thanks, Joel

P.S. 

--- foo.ml

#use "topfind";;

#require "zmq";;

open ZMQ;;
open ZMQ.Socket;;
open ZMQ.Poll;;

let context = init ();;

let pub_endpoint = "tcp://127.0.0.1:9997";;
let pull_endpoint = "tcp://127.0.0.1:9996";;

let pub = 
  let sock = Socket.create context pub in
  connect sock pub_endpoint;
  sock;;

let pull = 
  let sock = Socket.create context pull in
  connect sock pull_endpoint;
  sock;;

let timeout = 1000000 (* 1s *);;

let poll_set = of_poll_items [| pull, In; pub, Out |] in
match poll ~timeout poll_set with
  | [| pull, In |] ->
    let msg = recv pull in 
    ()
  | _ ->
    ()
;;

--- zmq.ml

module Socket :
sig
  type 'a t
  type 'a kind

  val pair   : [`Pair] kind
  val pub    : [`Pub] kind
  val sub    : [`Sub] kind
  val req    : [`Req] kind
  val rep    : [`Rep] kind
  val dealer : [`Dealer] kind
  val router : [`Router] kind
  val pull   : [`Pull] kind
  val push   : [`Push] kind

  val create : 'a kind -> 'a t

  val connect : 'a t -> string -> unit
  val bind : 'a t -> string -> unit

  val subscribe : [`Sub] t -> string -> unit
  val unsubscribe : [`Sub] t -> string -> unit

end = struct

  type 'a t = int

  type 'a kind = int

  let pair   = 0
  let pub    = 1
  let sub    = 2
  let req    = 3
  let rep    = 4
  let dealer = 5
  let router = 6
  let pull   = 7
  let push   = 8

  let create kind = 1

  let connect sock endpoint = ()
  let bind sock endpoint = ()

  let subscribe socket new_subscription = ()
  let unsubscribe socket old_subscription = ()

end

module Device :
sig

  val streamer  : [`Pull] Socket.t -> [`Push] Socket.t -> unit
  val forwarder : [`Sub] Socket.t -> [`Pub] Socket.t -> unit
  val queue     : [`Router] Socket.t -> [`Dealer] Socket.t -> unit

end = struct

  let streamer sock1 sock2 = ()
  let forwarder sock1 sock2 = ()
  let queue sock1 sock2 = ()

end

module Poll :
sig

  type t

  type event_mask = In | Out | In_out

  type poll_socket = [<`Pair|`Pub|`Sub|`Req|`Rep|`Dealer|`Router|`Pull|`Push] Socket.t
  type poll_item = (poll_socket * event_mask)

  val of_poll_items : poll_item array -> t

end = struct

  type t = string

  let of_poll_items items = "create poll set"

end



--------------------------------------------------------------------------
- for hire: mac osx device driver ninja, kernel extensions and usb drivers
---------------------+------------+---------------------------------------
http://wagerlabs.com | @wagerlabs | http://www.linkedin.com/in/joelreymont
---------------------+------------+---------------------------------------