From: "Christoph Höger" <christoph.hoeger@tu-berlin.de>
To: caml users <caml-list@inria.fr>
Subject: Re: [Caml-list] Cyclic type abbreviation
Date: Fri, 13 Nov 2015 14:46:55 +0100 [thread overview]
Message-ID: <5645E9CF.4070104@tu-berlin.de> (raw)
In-Reply-To: <E51C5B015DBD1348A1D85763337FB6D9EA03E44B@Remus.metastack.local>
Am 13.11.2015 um 14:37 schrieb David Allsopp:
>> Summary: what is supposedly wrong with it?
>
> I expect that what is wrong is that you can write:
>
> type node = int * tree * tree
> and tree = Some of node
> | None
>
> I don't know why you can't write [and tree = node option] instead.
Exactly, I do not understand why the builtin type option is handled
differently from a self-defined algebraic data type. I have a vague
understanding that the acyclic-property is sufficient for termination of
some operations on recursive types, but I wonder if option is just
missing a definition in the stdlib (so I could write a manifest, if that
would solve the issue) or if it is really something special.
--
Christoph Höger
Technische Universität Berlin
Fakultät IV - Elektrotechnik und Informatik
Übersetzerbau und Programmiersprachen
Sekr. TEL12-2, Ernst-Reuter-Platz 7, 10587 Berlin
Tel.: +49 (30) 314-24890
E-Mail: christoph.hoeger@tu-berlin.de
next prev parent reply other threads:[~2015-11-13 13:46 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-13 12:49 Christoph Höger
2015-11-13 13:15 ` Mr. Herr
2015-11-13 13:37 ` David Allsopp
2015-11-13 13:46 ` Romain Bardou
2015-11-13 14:24 ` Romain Bardou
2015-11-16 5:43 ` Ben Millwood
2015-11-16 16:42 ` peterfrey
2015-11-16 17:08 ` Pierrick Couderc
2015-11-13 13:46 ` Christoph Höger [this message]
2015-11-13 13:53 ` Mr. Herr
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