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=ham autolearn_force=no version=3.4.4 X-Google-Thread: 103376,3a7c118fd2cc64f9 X-Google-NewGroupId: yes X-Google-Attributes: gida07f3367d7,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII Path: g2news1.google.com!postnews.google.com!17g2000prr.googlegroups.com!not-for-mail From: Adam Beneschan Newsgroups: comp.lang.ada Subject: Re: A hole in Ada type safety Date: Thu, 12 May 2011 07:40:57 -0700 (PDT) Organization: http://groups.google.com Message-ID: <20de6e7b-8b76-4d84-877b-714e794aa7c1@17g2000prr.googlegroups.com> References: <87oc3odtci.fsf@mid.deneb.enyo.de> <715a5498-095c-4e61-8a09-8510c19b2553@s16g2000prf.googlegroups.com> <6fc0d396-40ca-4f32-8840-8091b94d9ddf@s14g2000vbi.googlegroups.com> NNTP-Posting-Host: 66.126.103.122 Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Trace: posting.google.com 1305211258 28911 127.0.0.1 (12 May 2011 14:40:58 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Thu, 12 May 2011 14:40:58 +0000 (UTC) Complaints-To: groups-abuse@google.com Injection-Info: 17g2000prr.googlegroups.com; posting-host=66.126.103.122; posting-account=duW0ogkAAABjRdnxgLGXDfna0Gc6XqmQ User-Agent: G2/1.0 X-HTTP-UserAgent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; WOW64; Trident/4.0; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.5.21022; .NET CLR 3.5.30729; .NET CLR 3.0.30618; .NET4.0C),gzip(gfe) Xref: g2news1.google.com comp.lang.ada:19235 Date: 2011-05-12T07:40:57-07:00 List-Id: On May 11, 10:51=A0pm, AdaMagica wrote: > Randy has already given the answer. > > Let me add a further remark (but note, I'm no language lawyer): > > You argue about the return statement. But there is no return statement > involved in the RM with Unchecked_Conversion, it's just compiler magic > that is being performed. (Being intrinsic, Unchecked_Conversion need > not be implemented in Ada. In fact, I think there is no code at all, > it just takes the bit pattern as is and reinterpretes it.) I think the poster's argument (inasmuch as I could follow it) was that although Unchecked_Conversion is implemented via compiler magic, it has to be defined in such a way that it *could* be written in Ada, and this would be a problem because you couldn't write a RETURN statement that would make it work. Or something like that. The basic problem is that there is no such rule (and never has been) that the function has to be writeable in Ada, despite the poster's assertion that "that goes back to the origins of Ada and has not change", so the whole argument is based on a false premise. The poster tried to make an argument to prove this premise, but I'm still trying to figure out what this argument was. It seems to be based on reading much more into certain language rules than is written there. -- Adam