Re: [Caml-list] Functors and classes

[John Prevost <j.prevost@gmail.com>]

The following model works for me.  The key problem here is that
there's no way to bring a class binding in in the way you want. 
That's not really a problem, except that you lose the ability to call
"new".  Perhaps the Dbi interface could be changed to allow for this? 
(Depending on how you do things, this could mean that a DbiPool could
itself be used as a Dbi module, somehow.)

It's also possible that I'm missing some way to otherwise do this.

John.


module TestThing =
  struct
    class connection =
      object
        method a = 1
	method b = 1
	method c = 1
      end
    let connect () = new connection
  end

module type ThingIntf = 
  sig
    type connection
    val connect : unit -> connection
  end

module type ThingPoolT =
  sig
    type connection
    val connect : unit -> connection
  end

module ThingPool (Thing : ThingIntf) :
    (ThingPoolT with type connection = Thing.connection) =
  struct
    type connection = Thing.connection
    let connect () = Thing.connect ()
  end

module X = ThingPool(TestThing)

let x = X.connect ()

let a = x #a
let b = x #b
let c = x #c

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