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-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,a00006d3c4735d70 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2004-01-14 05:25:52 PST Path: archiver1.google.com!news2.google.com!news.maxwell.syr.edu!uio.no!newsfeed.kolumbus.fi!not-for-mail From: Aatu Koskensilta Newsgroups: comp.lang.ada Subject: Re: Certified C compilers for safety-critical embedded systems Date: Wed, 14 Jan 2004 15:47:31 +0200 Organization: Elisa Internet customer Message-ID: References: <0F6Nb.1623$Tt.642@reader1.news.jippii.net> NNTP-Posting-Host: 212-246-60-38.adsl.tpo.fi Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Trace: phys-news1.kolumbus.fi 1074086751 19656 212.246.60.38 (14 Jan 2004 13:25:51 GMT) X-Complaints-To: abuse@kolumbus.fi NNTP-Posting-Date: Wed, 14 Jan 2004 13:25:51 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.2.1) Gecko/20030225 X-Accept-Language: en-us, en In-Reply-To: Xref: archiver1.google.com comp.lang.ada:4395 Date: 2004-01-14T15:47:31+02:00 List-Id: Georg Bauhaus wrote: > Aatu Koskensilta wrote: > : Because it seems flat out wrong. That > : > : [any compiler for a resonable language] either does not accept some > : legal programs, accepts some illegal programs, or never halts for some > : inputs > : > : does not in any sense follow from G?del's proof. The only way for it to > : be true is if "reasonable language" is defined as a language that is > : compile-time Turing-complete. Most languages currently in use are not. > > Can a self-hosting compiler then in theory decide whether it is > correct? For the former or the latter languages? I don't think I understand your question. Are you asking about a situation in which a compiler is used to compile itself? If so, certainly it can for both classes of languages accept itself as a legal program. Whether or not it's also correct in the sense of conforming to the relevant standard(s) is another matter, and I don't think you would expect a compiler to provide proofs of that sort. -- Aatu Koskensilta (aatu.koskensilta@xortec.fi) "Wovon man nicht sprechen kann, daruber muss man schweigen" - Ludwig Wittgenstein, Tractatus Logico-Philosophicus