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From: Martin Jambon <martin.jambon@ens-lyon.org>
To: Jacques Le Normand <rathereasy@gmail.com>
Cc: caml-list caml-list <caml-list@yquem.inria.fr>
Subject: Re: [Caml-list] default arguments in classes
Date: Wed, 17 Jun 2009 00:34:33 +0200	[thread overview]
Message-ID: <4A381DF9.8060502@ens-lyon.org> (raw)
In-Reply-To: <f74178430906161412u6d60f8c2m80dd90f02b57aa7d@mail.gmail.com>

Jacques Le Normand wrote:
> Hello list,
> I'm trying to define a method with a default argument, but I keep
> getting an error. Here's the code:
> 
> class foo  =
>   object (self)
>     method bar ?(baz="moo") () =
>     (new foo)#bar ~baz ()
>   end
> 
> and the error:
> 
> The expression "new foo" has type foo but is used with type
>   < bar : baz:string -> unit -> 'a; .. >
> Types for method bar are incompatible
> 
> how do I fix this?


Adding type annotations often helps:

class foo =
object (self)
  method bar ?(baz="moo") () : unit =
    ((new foo) # bar : ?baz:_ -> _) ~baz ()
end



Martin

-- 
http://mjambon.com/


      parent reply	other threads:[~2009-06-16 22:39 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-06-16 21:12 Jacques Le Normand
2009-06-16 22:06 ` [Caml-list] " Paolo Donadeo
2009-06-16 22:34 ` Martin Jambon [this message]

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