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=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,f25e853f410d55da X-Google-Attributes: gid103376,public From: William Clodius Subject: Re: Modula 2 Date: 1999/02/03 Message-ID: <36B8BC8C.2C67@lanl.gov>#1/1 X-Deja-AN: 440356540 Content-Transfer-Encoding: 7bit References: <78abg4$cnc$1@its.hooked.net> <78i8s4$hth$1@its.hooked.net> <78iq2m$br9$1@nnrp1.dejanews.com> <794gg7$ib$1@nnrp1.dejanews.com> <7963q0$ail$1@nnrp1.dejanews.com> <7973lb$mdl$1@remarQ.com> <797595$ede@drn.newsguy.com> <797io4$jt7$1@nnrp1.dejanews.com> <797q7f$r60$1@nnrp1.dejanews.com> <36B7996F.500F@lanl.gov> Content-Type: text/plain; charset=us-ascii Organization: Los Alamos National Lab Mime-Version: 1.0 Newsgroups: comp.lang.ada Date: 1999-02-03T00:00:00+00:00 List-Id: Robert A Duff wrote: > > Wirth's language descriptions are quite short, primarily because he > tends to leave out a lot of important details, IMHO. That's his style. > I would expect a definition of any of Wirth's languages, suitable for > standardization, would be much longer than Wirth's original, even if > there were *no* extensions or use of VDM. > Yes it would be longer, but not fifteen to twenty times longer. Note for example that ISO Pascal ISO 7185:1990 is 78 pages long, which is two to three times the size of Wirth's original definition, and extended Pascal is 214 pages long, about six to eight times the size of Wirth's original definition after adding numerous extensions. (Yes I agree page count can be misleading, but that is the main data I have at the moment.) Wirth's Modula 2 was a more complicated than his Pascal, but not a lot more complicated. A Modula 2 standard giving the main syntax and semantics in 100-125 pages and additional libraries in 100-125 additional pages would have been viewed as a reasonable extension and clarification. To put it into other perspectives: The Modula 2 base language document is (in terms of page count) almost 40% larger than the Ada 95 standard, without providing object orientation or generics. Including the separate later documents giving these extensions results in a nominal definition well over 50% larger than the Ada standard, but still less functional than Ada 95. The Modula 2 base language document is (in terms of page count) about 2% smaller than the C++ standard. The library is not nearly as functional as that of C++. Algol 68's two level grammar, that provides precision comparable to the VDM, was used to define a language of comparable complexity (excluding libraries) in complete detail in, Robert Dewar will probably correct this, I believe a little under 200 pages. The VDM specification has not fulfilled the role the committee espected for it when standardization started. They hoped to be able use the VDM as input to automatic tools to verify the self consistency of the standard, but resource limitations kept the tools from being completed. It has instead resulted in extra work that delayed publication and made the standard more difficult to read for those unfamiliar with VDM (most compiler writers and reviewers of the draft standard are unfamiliar with VDM). The exception handling mechanism specified in the Modula 2 document is very different from PL/I, Ada, or C++, and was widely viewed as an unwise experiment for a language standard. The libraries as a whole were rather experimental and had little match to those described by Wirth in his Modula 2 texts. Some "countries", e.g., Sweden, that did not file formal objections to the standard, included comments to the effect that the standard when adopted would kill the language. -- William B. Clodius Phone: (505)-665-9370 Los Alamos Nat. Lab., NIS-2 FAX: (505)-667-3815 PO Box 1663, MS-C323 Group office: (505)-667-5776 Los Alamos, NM 87545 Email: wclodius@lanl.gov