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From: Michael <micha-1@fantasymail.de>
Reply-To: micha-1@fantasymail.de
To: <caml-list@inria.fr>
Subject: [Caml-list] a class as method parameter...
Date: Fri, 28 May 2004 11:25:50 +0200
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Hi,

I don't understand why this doesn't work:

class one = object
  val name = "test"
  method name = name
end;;
class two = object
  method take_one o -> o#name
end;;

that gives:
Some type variables are unbound in this type:
  class two : object method take_one : < name : 'a; .. > -> 'a end
The method take_one has type (< name : 'b; .. > as 'a) -> 'b where 'a
is unbound

I have to declare:
class two = object
  method take_one : 'a. (#one as 'a) -> string = fun o ->  o#name
end;;

.. to get it work (from chapter 3.10 )

why has it to be declared this way? 
( and not:
class two = object
  method take_one ( o : #one ) =  o#name
end;;

which also does not work:
The method take_one has type (#one as 'a) -> string where 'a is unbound ) ??

thanks,
 Michael
 



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