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,cc9d51d301f523ef X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2002-12-19 02:32:47 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!newsfeed.icl.net!newsfeed.fjserv.net!news.teledanmark.no!news01.chello.no!uio.no!Norway.EU.net!dax.net!juliett.dax.net!not-for-mail Newsgroups: comp.lang.ada Subject: Re: Newbee question References: <3DFB9067.2040600@acm.org> <0dRK9.37601$xH3.400905@weber.videotron.net> <2bTK9.62545$hK4.5163007@bgtnsc05-news.ops.worldnet.att.net> <3dfdab08.5187148@news.demon.co.uk> From: Ole-Hjalmar Kristensen Message-ID: <7vvg1qnvtn.fsf@vlinux.voxelvision.no> User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.1 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Thu, 19 Dec 2002 10:32:04 GMT NNTP-Posting-Host: 193.216.12.150 X-Complaints-To: abuse@tele2.no X-Trace: juliett.dax.net 1040293924 193.216.12.150 (Thu, 19 Dec 2002 11:32:04 MET) NNTP-Posting-Date: Thu, 19 Dec 2002 11:32:04 MET Organization: Tele2 Norway AS Public Access X-Received-Date: Thu, 19 Dec 2002 11:32:46 MET (news01.chello.no) Xref: archiver1.google.com comp.lang.ada:32072 Date: 2002-12-19T10:32:04+00:00 List-Id: "Marin David Condic" writes: > > Well, my observations have come about from trying to interface along > communications paths with other things that are not necessarily Ada. > Sometimes things overlap byte, word or longword boundaries. Having a > compiler tell me I can't do that instantly makes the rep-clause useless to > me because the only way I can guarantee that I can handle all the cases that > come up - or ever may come up - is to go to a byte array and start picking > out the bits myself, ala C. Maybe my problems aren't the most common ones, > but it happens enough to make one wish that the rep clause could be used to > arbitrarily overlay a contiguous stream of bits without restrictions - or > you start asking yourself "Why bother having a rep clause?" The C answer is > "We don't have a rep clause - go pick the bits apart yourself." The Ada > answer seems to have been "Here. Let me help you with all that bit > twiddling. But only if you agree not to twiddle all the bits you might want > to twiddle..." > > I'll give you the compiler efficiency issues. But that just suggests that > perhaps some other construct is necessary for the language to be able to > express representation and then deal with packing/unpacking. I'd be happy if > I could somehow express the record representation in some manner that let me > put the record on the wire or take the record off the wire and then do some > kind of "Pack/Unpack" operations if I wanted to do anything computational. I > don't have a prepackaged answer, but it is something to think about... > > MDC > -- > ====================================================================== > Marin David Condic > I work for: http://www.belcan.com/ > My project is: http://www.jast.mil/ > > Send Replies To: m c o n d i c @ a c m . o r g > > "I'd trade it all for just a little more" > -- Charles Montgomery Burns, [4F10] > ====================================================================== > > I picked up this on the net by chance, perhaps Lutz could comment if this could be an answer to such problems? : 16.00 Workshop 1 Generic Bidirectional Mapper Vorgestellt wird ein Yacc-Nachfolger, der ausreichen komplex ist, um die praktischen externen Datenstrukturen in einem Ritt zu lesen und zu schreiben. Lutz Donnerhacke -- Ole-Hj. Kristensen ****************************************************************************** * You cannot consistently believe this sentence. ******************************************************************************