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Date: 25 May 96 16:25:56 EDT
From: ESPERET PHILIPPE <100060.2106@compuserve.com>
To: liste Caml <caml-list-request@pauillac.inria.fr>
Subject: Oo.copy
Message-ID: <960525202556_100060.2106_JHB98-1@CompuServe.COM>
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%  ocaml1.tex 25-5-1996 (23h:16)



%%%%%%%%%%%%%%
Philippe Esperet (France)
Fax : (33-1) 46 56 83 68
email 100060.2106@compuserve.com 



   I cannot understand how to access a fresh copy of an object with
O'Caml (Oo seems normally to copy only pointers).  Thank you if someone
can explain me how to get such a copy (please see below for an example).

   One related problem is : the documentation for O'Caml exists but is not
so thick ; it could be useful to have a list where true beginners in
OCaml might ask their questions and find examples.

   

(*
#use "C:/OCAML/esperet/email3.ml";;
*)




class virtual 'a matrix(sz,init:int*'a) as self=
  val size=sz
  val m=Array.create_matrix sz sz init
  val zero=init 
  virtual printa:'a -> unit
  (*method copy()=new matrix(size,zero)
   forbidden: One cannot create instances of the virtual class matrix*)
  method m=m
  method set(i,j,nval:int*int*'a)= m.(i).(j) <- nval
  method build(f:int->int->'a)=for i=0 to size-1 do
                                 for j=0 to size-1 do 
                                   m.(i).(j)<- f i j done done;self
  method print()=for i=0 to size-1 do
                   for j=0 to size-1 do 
                     self#printa m.(i).(j);
                     print_char ';' done; 
                   print_newline() done
  end




class int_matrix (sz:int)=
  inherit (int) matrix (sz,0)
  method printa=print_int
end


let m=new int_matrix 3;;
(m#build (fun i j->i+j))#print();;
m#print();;
let n=Oo.copy m;;
(*let nn=m#copy();;*)
m#set(1,1,66);;
n#print();;
(*nn#print();;*)