From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00
	autolearn=unavailable autolearn_force=no version=3.4.4
Path: 
 border1.nntp.dca3.giganews.com!border3.nntp.dca.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!goblin2!goblin.stu.neva.ru!feeder.erje.net!eu.feeder.erje.net!eternal-september.org!feeder.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: System.Address to Access to function/procedure conversion
Date: Sun, 28 Jul 2013 20:23:15 +0100
Organization: A noiseless patient Spider
Message-ID: <ly7ggasd3w.fsf@pushface.org>
References: <kt3d9j$vmp$1@adenine.netfront.net>
 <15i0rfwzpj7cy$.ob5l4ffr5iqa$.dlg@40tude.net>
 <kt3q27$18qs$1@adenine.netfront.net>
Mime-Version: 1.0
Content-Type: text/plain
Injection-Info: mx05.eternal-september.org;
 posting-host="d88aa8a0fafe4f7fb3eb325f8f3d97d0";
 logging-data="24180"; mail-complaints-to="abuse@eternal-september.org";
 posting-account="U2FsdGVkX1/GSRX2wETqGj5kQm+WsbZZXg/QzyHupDA="
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (darwin)
Cancel-Lock: sha1:xns8s4Vhcg08s9AIaUc6GC3SJ/M=
 sha1:CVLbMiqfwR/nV2o+A788mAxDLdI=
X-Original-Bytes: 1841
Xref: number.nntp.dca.giganews.com comp.lang.ada:182742
Date: 2013-07-28T20:23:15+01:00
List-Id: <comp.lang.ada>

Tarek Ghaleb <invalid@invalid.org> writes:

> Ideally, Callback() is not the actual imported callback() but it takes
> Ada friendly parameters and does any type conversions needed then
> calls the imported callback() function.

I find this confusing because I'm used to thinking of the procedure-to-
be-called-back as the 'callback', and what you're talking about here is
the registration interface. But if that's FLTK's nomenclature ...

Especially if the called-back procedure takes parameters, you're going
to have to do a conversion on the way back as well! I think you might be
able to do something with a generic, but .. you can't make a generic
formal type definition that declares an "access to procedure with this
parameter profile" type.