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 X-Google-Thread: 103376,a00006d3c4735d70 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2004-01-13 23:58:52 PST Path: archiver1.google.com!news2.google.com!news.maxwell.syr.edu!news.tele.dk!news.tele.dk!small.news.tele.dk!news100.image.dk!fi.sn.net!newsfeed2.fi.sn.net!feeder2.news.jippii.net!feeder1.news.jippii.net!reader1.news.jippii.net!53ab2750!not-for-mail From: Aatu Koskensilta User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.5) Gecko/20030925 X-Accept-Language: en-us, en MIME-Version: 1.0 Newsgroups: comp.lang.ada Subject: Re: Certified C compilers for safety-critical embedded systems References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Message-ID: <0F6Nb.1623$Tt.642@reader1.news.jippii.net> Date: Wed, 14 Jan 2004 10:01:26 +0200 NNTP-Posting-Host: 195.74.11.141 X-Complaints-To: newsmaster@saunalahti.com X-Trace: reader1.news.jippii.net 1074067132 195.74.11.141 (Wed, 14 Jan 2004 09:58:52 EET) NNTP-Posting-Date: Wed, 14 Jan 2004 09:58:52 EET Organization: Saunalahti Customer Xref: archiver1.google.com comp.lang.ada:4383 Date: 2004-01-14T10:01:26+02:00 List-Id: Alexandre E. Kopilovitch wrote: > Aatu Koskensilta wrote: >> >>Where do you get this curious idea about G�del's proof? > > Why do you call that reference to G�del's proof "curious"? 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. Also, from the compile-time Turing-completeness it follows only that the compiler will fail to halt for some illegal program, provided the language is not unreasonable enough to declare valid programs with non-halting compile-time constructions. > Or you imply that theorems of (mathematical) logic can't have a sense and > therefore shouldn't be mapped to reality at all? -:) No, mathematical logic is very relevant to computer science. -- Aatu Koskensilta (aatu.koskensilta@xortec.fi) "Wovon man nicht sprechen kann, daruber muss man schweigen" - Ludwig Wittgenstein, Tractatus Logico-Philosophicus