From: briand@aracnet.com
To: Damien <Damien.Pous@ens-lyon.fr>
Cc: caml-list@inria.fr
Subject: Re: [Caml-list] 'b is unbound
Date: Wed, 12 May 2004 19:54:05 -0700 [thread overview]
Message-ID: <16546.58189.824443.134275@soggy.deldotd.com> (raw)
In-Reply-To: <20040512134350.7be8c813.Damien.Pous@ens-lyon.fr>
>>>>> "Damien" == Damien <Damien.Pous@ens-lyon.fr> writes:
Damien> polymorphic methods require to be explicitly typed (this
Damien> kind of type inference should lead to the one for system F)
After little more investigation I found that the following will work :
method op (j:(float, Bigarray.float64_elt, Bigarray.c_layout) Bigarray.Array2.t) f x =
Seems very straightforward. However there is one confusing aspect :
method op (j:(float, Bigarray.float64, Bigarray.c_layout) Bigarray.Array2.t) f x =
error -> Unbound type constructor Bigarray.float64
? Aha ! float64 in bigarray.mli is not a type but a val.
So now my method is no longer polymorphic, right ?
So everything makes sense until I go back to my bigarray test file :
let a = Bigarray.Array2.create Bigarray.float64 Bigarray.c_layout n n;;
is OK.
let a = Bigarray.Array2.create Bigarray.float64_elt Bigarray.c_layout n n;;
error -> Unbound value Bigarray.float64_elt
Then I looked at the definition for create and it finally makes sense.
However I would argue that it is also _very_ confusing.
Why doesn't create simply take the type, i.e. ..._elt instead of
('a, 'b) kind ??
Brian
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prev parent reply other threads:[~2004-05-13 2:54 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-05-12 6:31 briand
2004-05-12 11:43 ` Damien
2004-05-12 19:11 ` briand
2004-05-13 2:54 ` briand [this message]
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