Michael wrote:
> it seems that I'm not able to figure out how to do  this:
> 
> class baseclass = object(this)
>   method asBase = (this :> baseclass)
> (* ... *)	
> end;;
> 
> class ex = object inherit baseclass method name = "ex" end
> 
> type state_rec = { mutable state:  'a. #baseclass as 'a };;

There is no value of type: forall 'a. #baseclass as 'a.

I think what you want to do is:

  type state_rec = { mutable state: exists 'a. #baseclass as 'a };;

You can actually do this with objects:

  type state_rec = { mutable state : baseclass }

  { state = (x :> baseclass) }

cheers,
Jérémie