From: Hendrik Boom <hendrik@topoi.pooq.com>
To: caml-list@inria.fr
Subject: [Caml-list] reverse coercions
Date: Fri, 10 Jun 2016 14:12:22 -0400 [thread overview]
Message-ID: <20160610181222.GA27973@topoi.pooq.com> (raw)
In http://caml.inria.fr/pub/docs/u3-ocaml/ocaml-objects.html it says:
reverse coercions from a supertype to a supertype are never possible in
OCaml.
(a) Might one of these 'supertype's actually be a 'subtype'?
(b) Is there any way to do a run-time type-test on a value of a
specific statically known supertype to test whether it is actually a
value of a known specified subtype, and if so to proceed to use it as
that subtype?
If so, I'd like to use this in a suite of pattern-directed rule
invocations.
If not, I'd like to know if there are any well-known efficient ways
around this. Of course I can effectively Godel-encode my data
structures using lists, and interpret all my patterns and the
application types I woyd have rather expressed as OCaml types, but I'm
looking for something more elegant, statically checked, and
efficient.
-- hendrik
next reply other threads:[~2016-06-10 18:12 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-10 18:12 Hendrik Boom [this message]
2016-06-10 18:25 ` dario.teixeira
2016-06-10 19:05 ` [Caml-list] octothorpes and backticks? Hendrik Boom
2016-06-10 20:04 ` Anthony Tavener
2016-06-10 18:34 ` [Caml-list] reverse coercions Gerd Stolpmann
[not found] ` <CAPFanBFa+MJzvt_KYmReuHSzRpD=fT=nEaXB4c7dMwWSL3w7Vg@mail.gmail.com>
2016-06-10 18:59 ` Hendrik Boom
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20160610181222.GA27973@topoi.pooq.com \
--to=hendrik@topoi.pooq.com \
--cc=caml-list@inria.fr \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).