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: 103376,74b55538385b7366 X-Google-Attributes: gid103376,public From: Keith Thompson Subject: Re: Ada safety road Was: Which is right ... Date: 1999/06/07 Message-ID: #1/1 X-Deja-AN: 486799863 References: <928083159.436.79@news.remarQ.com> <928174549.336.98@news.remarQ.com> <7iuqkc$ln6$1@nnrp1.deja.com> <928529202.956.79@news.remarQ.com> <928569312.951.42@news.remarQ.com> <7jb1l9$694$1@nnrp1.deja.com> <928703068.617.98@news.remarQ.com> <1999Jun6.181633.1@eisner> X-Complaints-To: usenet@nusku.cts.com X-Trace: nusku.cts.com 928788301 2327 198.68.168.21 (7 Jun 1999 20:45:01 GMT) Organization: CTS Network Services NNTP-Posting-Date: 7 Jun 1999 20:45:01 GMT Newsgroups: comp.lang.ada Date: 1999-06-07T20:45:01+00:00 List-Id: kilgallen@eisner.decus.org (Larry Kilgallen) writes: > In article <928703068.617.98@news.remarQ.com>, "Vladimir Olensky" writes: > > But I see one problem here. All this information is scattered > > around RM. > > In order to be definitive, the RM should not duplicate information in > various locations, and thus cannot be in the ideal exposition format > for all purposes. The RM already has several "informative" annexes, which are not strictly part of the standard. Annexes K (attributes) and L (pragmas) are particularly useful, even though (or rather *because*) they duplicate information scattered around the RM. An informative annex listing all occurrences of erroneous execution and bounded errors would have been useful. As I was writing this, I realized we already have the next best thing. The entry for "erroneous" in the RM's index refers to all the places in the RM where the term is used; likewise for "bounded error". This brings up a pet peeve of mine: the word "erroneous" was a poor choice of terminology. It's an existing English word with a well-defined meaning. When I use the word in an Ada context, I very often have to explain the Ada-specific meaning. It also fails to make it clear that it's the execution of a construct that's erroneous, not the construct itself. Norman Cohen, in his book "Ada as a Second Language", uses the phrase "unbounded error", which is much clearer. Another good term is "undefined behavior", used by the C and C++ standards for (essentially) the same concept. If we could keep people from using the word "erroneous" outside the phrase "erroneous execution", there wouldn't be as much of a problem, but that's not going to happen. -- Keith Thompson (The_Other_Keith) kst@cts.com San Diego Supercomputer Center <*> One of the great tragedies of ancient history is that Helen of Troy lived before the invention of the champagne bottle.