From: Jean Balthazar <jean.balthazar.fr@gmail.com>
To: caml-list@inria.fr
Subject: Interpretation of an error message "type ('a, 'b) t should be ('a, 'c) t" in a signature?
Date: Mon, 20 Apr 2009 22:45:45 +0200 [thread overview]
Message-ID: <d83f21e60904201345o21881293l7d4f80373a6b6cb4@mail.gmail.com> (raw)
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Dear caml-list,
I try to define the signature of three interdependant classes that should
then be derived and completed for various implementation. The code below
causes the strange error messsage:
File "tmp.ml", line 4, characters 7-92:
In the definition of job, type ('a, 'b) batch should be ('a, 'c)
batch
Can you explain what is wrong with this signature?
I was unable to find an answer to a similar problem in the archives.
Thank you very much.
Jean
----------------------------------------------------------------------------
module type JOB =
sig
type ('a, 'b) batch = private < build : 'a job -> ('a priority * 'a) list
-> 'b job; .. >
and 'b priority = private < next : 'b priority; .. >
and 'a job = private < create_batch : 'c.('a -> 'c) -> ('a, 'c) batch;
.. >
end
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next reply other threads:[~2009-04-20 20:46 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-20 20:45 Jean Balthazar [this message]
2009-04-21 2:45 ` [Caml-list] " Jacques Garrigue
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