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-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,7e60c1d99ae3ffa1 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2002-09-13 14:03:40 PST Path: archiver1.google.com!news1.google.com!sn-xit-02!sn-xit-06!sn-post-02!sn-post-01!supernews.com!corp.supernews.com!not-for-mail From: "Randy Brukardt" Newsgroups: comp.lang.ada Subject: Re: Announce: The Ultimate SI Units Cracker Date: Fri, 13 Sep 2002 15:54:02 -0500 Organization: Posted via Supernews, http://www.supernews.com Message-ID: References: <3D809F51.299A6634@despammed.com> <3D820229.E1B1BEC8@despammed.com> X-Newsreader: Microsoft Outlook Express 4.72.3612.1700 X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3719.2500 X-Complaints-To: abuse@supernews.com Xref: archiver1.google.com comp.lang.ada:28956 Date: 2002-09-13T15:54:02-05:00 List-Id: Wes Groleau wrote in message <3D820229.E1B1BEC8@despammed.com>... >> It was considered for Ada 9x, but was rejected as having insufficient >> value for the substantial changes that would be required for compilers. >> Most existing Ada compilers do not put attributes in the symboltable; >> they do not have visibility, and so on. > >But they do for 'Write & 'Read, so why not for others? Not really. 'Read and 'Write don't have visibility at all (they have to be redefined before freezing). And, in Janus/Ada, they're not actually in the symbol table -- they are part of the type. (We don't keep type information in the symbol table at all, just the names of the types). Types (in Janus/Ada) don't have visibility; they always exist. And, finally, these items have hard coded definitions in the types; there is no mechanism for adding others (particularly user defined ones). Other compilers may differ of course, but user-defined attributes would take several months of work to implement in Janus/Ada -- and no one had a compelling enough example to justify making implementors do that sort of work. Randy.