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From: Goswin von Brederlow <goswin-v-b@web.de>
To: Dario Teixeira <darioteixeira@yahoo.com>
Cc: caml-list@yquem.inria.fr
Subject: Re: [Caml-list] Merging object signatures
References: <313968.60910.qm@web111509.mail.gq1.yahoo.com>
Date: Thu, 04 Nov 2010 21:01:49 +0100
In-Reply-To: <313968.60910.qm@web111509.mail.gq1.yahoo.com> (Dario Teixeira's
	message of "Thu, 4 Nov 2010 11:55:47 -0700 (PDT)")
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X-Spam: no; 0.00; merging:01 variants:01 'val:01 foobar:01 foo:01 foo:01 sig:01 val:01 foobar:01 val:01 struct:01 mfg:98 polymorphic:01 signatures:01 signatures:01 

Dario Teixeira <darioteixeira@yahoo.com> writes:

> Hi,
>
> Similarly to polymorphic variants, is there a way for object signatures to
> be merged by type name?  Consider the example at the end; I'm wondering if
> it is possible for the declaration of 'foobar' to be something along the
> lines of 'val foobar: int -> int -> < foo_t; bar_t >' instead of needing to
> explicitly list all the methods in foo_t and bar_t.
>
> Thanks in advance for your help!
> Best regards,
> Dario Teixeira
>
>
> module Test:
> sig
> 	type foo_t = < a: int >
> 	type bar_t = < b: int >
>
> 	val foobar: int -> int -> < a:int; b: int >
>
> 	(* val foobar: int -> int -> < foo_t; bar_t > *)
> end =
> struct
> 	type foo_t = < a: int >
> 	type bar_t = < b: int >
>
> 	class foo a = object method a: int = a end
> 	class bar b = object method b: int = b end
>
> 	let foobar a b =
> 	object
> 		inherit foo a
> 		inherit bar b
> 	end
> end

Can't you make foo_t and bar_t class types and foobar_t inherits them
both?

MfG
        Goswin