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=0.4 required=5.0 tests=BAYES_00,FORGED_MUA_MOZILLA autolearn=no autolearn_force=no version=3.4.4 X-Google-Thread: 103376,5412c98a3943e746 X-Google-NewGroupId: yes X-Google-Attributes: gida07f3367d7,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Received: by 10.68.201.129 with SMTP id ka1mr2098312pbc.6.1331717047865; Wed, 14 Mar 2012 02:24:07 -0700 (PDT) Path: h9ni24596pbe.0!nntp.google.com!news1.google.com!news4.google.com!feeder1-2.proxad.net!proxad.net!feeder2-2.proxad.net!newsfeed.arcor.de!newsspool3.arcor-online.net!news.arcor.de.POSTED!not-for-mail Date: Wed, 14 Mar 2012 10:24:08 +0100 From: Georg Bauhaus User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:10.0.2) Gecko/20120216 Thunderbird/10.0.2 MIME-Version: 1.0 Newsgroups: comp.lang.ada Subject: Re: Verified compilers? References: <9207716.776.1331054644462.JavaMail.geo-discussion-forums@ynaz38> <4edda5mav3cf$.149pbgyxl1wx5.dlg@40tude.net> <9rplcgF5a2U1@mid.individual.net> <1psd0g0womgxi.1sle7ol12x3d5.dlg@40tude.net> <9rsahhFmr3U1@mid.individual.net> <9rvdjvFfa8U1@mid.individual.net> <4pp58h1br5sp$.yylr20e5vzxb.dlg@40tude.net> <9s1s7tF6pcU1@mid.individual.net> <1oln2mjlozzh5$.1mxrd97lrgndo.dlg@40tude.net> <9s4mseFuoaU1@mid.individual.net> <9sb3l3Fs4oU1@mid.individual.net> In-Reply-To: <9sb3l3Fs4oU1@mid.individual.net> Message-ID: <4f6063b7$0$6642$9b4e6d93@newsspool2.arcor-online.net> Organization: Arcor NNTP-Posting-Date: 14 Mar 2012 10:24:07 CET NNTP-Posting-Host: 155fe292.newsspool2.arcor-online.net X-Trace: DXC=A8:_1HVHk=dOKO]LCQ@0g`A9EHlD;3Ycb4Fo<]lROoRa8kFejVh0Q46YNao\ThKag_KjN\ On 14.03.12 09:36, Niklas Holsti wrote: > On 12-03-12 11:43 , Dmitry A. Kazakov wrote: >> No computer can parse infinite language >> or compute incomputable. If you want to handle such stuff [and you must all >> the time!] you have to map it onto some finite/computable framework and >> deal within the latter. > > Exactly. But since our present computers can deal with very large numbers and programs indeed, the mathematical and technical methods we use for handling programming languages and programs cannot depend on this finiteness, but must use methods that apply to numbers and programs of unbounded size, but still of constrained form. Grammars are good for that, IMO. Side note: WRT finiteness, language designers have made one particular mistake again and again, following a convention, by telling programmers about some type called REAL. The set of supposed real numbers that programmers have heard about before, in math lessons, is not finite---though no one has ever seen it, giving rise to the question of a possible misunderstanding of infinity. The values of reals include numbers that are not rational, not a ratio, or fraction, that is. What the language designers usually mean, though, is some finite Fraction_with_Split_Shifting thing, having infinitesimally little to do with the reals. Consequence: an infinite supply of surprises, cause by the name REAL.