Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!uunet!wang!news From: rschwartz@OFFICE.WANG.COM (R. Schwartz@Wang R&D Net) Newsgroups: comp.std.internat Subject: Re: rendering v. processing (was "re: FOOTWARE SWOOSH") Message-ID: Date: 2 May 91 20:43:24 GMT Sender: news@wang.com Organization: Mail to News Gateway Lines: 63 I was a bit sloppy in the construction of my arguments in my original post. Prof. Birnbaum has pointed out a number of weaknesses, some of which reflect inaccuracies in my writing, and some of which indicate that I had not given enough thought to the issues. Kyongsok Kim has picked up on one of the issues that reflects both failings. I have yet to see Prof. Birnbaum's response posted, although I have an e-mail copy. When it appears, I will post some clarifications regarding issues that he raised, and I look forward to hearing from others about the basic socio-political difference between our respective positions. kkim@plains.NoDak.edu (kyongsok kim) writes: > As far as I know, #integers is NOT finite; however, #characters is FINITE > (although it may be VERY LARGE), isn't it? I have hard time figuring out > a parallelism here. Please correct me if I am missing something here? My intention was only to illustrate that we do make abstractions that are geared towards making implementations reasonable. However, I might argue that the analogy is fairly close: the set of characters is finite, but of unknown extent and with no provable upper bound on it's membership. This being the case, it is not possible to specify a maximum 'size' (either for a bit encoding, a byte-sequence encoding, a Turing machine, or any other mechanism) of a single character. I don't have trouble believing that the set of characters has no provable upper bound on membership. I also argue that even if there is a provable boundary today, that it is not static. I would contend that the size of the set must be monotonically increasing as new "written culture" (cf. DB's post) is created and/or discovered but (thanks to Historians, Linguists, Archaeologists, et al.) not often irrevocably lost. My argument on this point is lacking somewhat in intellectual rigor [ that's what eight years of implementation work can do to you :-) ], but I doubt I can be proven incorrect. I do not mean to imply that no abstraction can be devised to represent any member of an infinite set. If I recall correctly, X.409 / ASN.1 encoding provides an elegant method for representing arbitrary size integers. My intention was to illustrate that it is always possible to choose a member of the set of size sufficient to overflow available space in an implementation of any abstraction, either by exceeding fixed limits implied in the abstraction itself, or by exceeding limits on resources. For characters, this is as true as it is for integers. In a fixed-width bit encoding method, eventually one can always devise enough characters to exhaust the available values. In a completely open-ended variable-width- byte-sequence encoding, it is possible to construct a character that overflows storage limits. In a scheme in which a limited sequence of members of a subset of the fixed-width characters (i.e., diacritics) can be applied to a single member of a different subset of the fixed-width characters (i.e., base symbols), the base subset and diacritic subset are both instances of fixed-width bit encodings, ergo the available values of both may eventually be exhausted. So, yes, the analogy as I stated it initially is weak. Never-the-less, I believe that if we accept that the set of characters is finite but of unknown extent, the analogy does hold. And the purpose that I had in mind was to demonstrate that the pragmatic concerns of implementors are not only legitimate... they are inevitable. rich schwartz (All views expressed are my own, and not Wang Labs, Inc.'s.) rschwartz@office.wang.com VOICE (508) 967 5027 FAX (508) 967 0947 Wang Labs, Inc., M/S 019-58A, 1 Industrial Ave., Lowell, MA 01851