type and class definition : recursion

type and class definition : recursion

[pbrisset]

Hello,

I would like to define a class and a type with a mutual recursion between
them. Something like

	type t = A
	       | B of c
	and class c (x:t) =
          val mutable value = x
	end

Is it possible with O'caml ?

--------------
Pascal Brisset
ENAC, 7 avenue Edouard Belin, BP 4005, F-31055 Toulouse Cedex, France
Tel: +33 62 17 40 53, E-mail: pbrisset@eis.enac.dgac.fr, Fax: +33 62 17 41 43

Re: type and class definition : recursion

[Christian Boos]

pbrisset@eis.enac.dgac.fr writes:
 > I would like to define a class and a type with a mutual recursion between
 > them. Something like
 > 
 > 	type t = A
 > 	       | B of c
 > 	and class c (x:t) =
 >           val mutable value = x
 > 	end
 > 
 > Is it possible with O'caml ?
 > 
 > --------------

Yes :

#type 'a t = A | B of 'a;;
type 'a t = A | B of 'a
#class c (x : 'a t) : 'a = val mutable value = x end;;
class c ('a t) : 'a =
  val mutable value : 'a t
end
#let foo = new c A;;
val foo : c = <obj>
#let bar = new c (B foo);;
val bar : c = <obj>
#

-- Christian