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: 103376,93a8020cc980d113 X-Google-Attributes: gid103376,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news1.google.com!border1.nntp.dca.giganews.com!nntp.giganews.com!nx02.iad01.newshosting.com!newshosting.com!198.186.194.251.MISMATCH!news-out.readnews.com!transit4.readnews.com!panix!newsfeed-00.mathworks.com!nntp.TheWorld.com!not-for-mail From: Robert A Duff Newsgroups: comp.lang.ada Subject: Re: What is wrong with Ada? Date: Sat, 14 Apr 2007 18:49:51 -0400 Organization: The World Public Access UNIX, Brookline, MA Message-ID: References: <1176150704.130880.248080@l77g2000hsb.googlegroups.com> <461B52A6.20102@obry.net> <461BA892.3090002@obry.net> <82dgve.spf.ln@hunter.axlog.fr> <1176226291.589741.257600@q75g2000hsh.googlegroups.com> <4eaive.6p9.ln@hunter.axlog.fr> <1rbtw92apxpl1.1ednvo8v6oiq8$.dlg@40tude.net> NNTP-Posting-Host: shell01.theworld.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: pcls6.std.com 1176590991 15284 192.74.137.71 (14 Apr 2007 22:49:51 GMT) X-Complaints-To: abuse@TheWorld.com NNTP-Posting-Date: Sat, 14 Apr 2007 22:49:51 +0000 (UTC) User-Agent: Gnus/5.1008 (Gnus v5.10.8) Emacs/21.3 (irix) Cancel-Lock: sha1:bPYyPCFMAtQVadYxVnGYo3oIZe0= Xref: g2news1.google.com comp.lang.ada:15027 Date: 2007-04-14T18:49:51-04:00 List-Id: Markus E Leypold writes: > But the set of all inputs is not necessarily finite -- i.e. in the > case that the user might enter one data item after the other and get > some answer about that item until he enters a end-of-input symbol > (stupid example: an interactive prime tester). Since it is nonsense to > artificially restrict the length of the user interaction just to get a > finite set of input sequences, we will have to live with a infinite > number of potential inputs to the program. So the paths covered are > also inifinite (program state is still finite since the machine has > only finite state). Yes. But I want to know that my program will work properly on any computer, including ones that don't exist yet. I don't know how big or fast computers will be in ten years. That's why it's useful to reason about computers that have unbounded amounts of memory (and time!) -- e.g. Turing machines -- even though we will never be able to build such a thing. - Bob