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: 103376,92471489ebbc99c6 X-Google-Attributes: gid103376,public From: dewar@gnat.com Subject: Re: Y2K Issues Date: 1998/10/31 Message-ID: <71doo5$cem$1@nnrp1.dejanews.com>#1/1 X-Deja-AN: 406856640 References: <71aejn$ped$1@nnrp1.dejanews.com> X-Http-Proxy: 1.0 x2.dejanews.com:80 (Squid/1.1.22) for client 205.232.38.14 Organization: Deja News - The Leader in Internet Discussion X-Article-Creation-Date: Sat Oct 31 01:22:14 1998 GMT Newsgroups: comp.lang.ada X-Http-User-Agent: Mozilla/2.02 (OS/2; I) Date: 1998-10-31T00:00:00+00:00 List-Id: In article , Matthew Heaney wrote: > dewar@gnat.com writes: > > > P.S. Why don't we want customers adding grandchildren of Ada -- simple, they > > would potentially depend on internal private parts of the implementation of > > these packages which we feel free to change without notice at any time! > > But isn't that the whole point adding the (grand)child - to get at the > underlying representation of predefined types? > > If I add a child to Ada.Calendar, and the vendor changes the internal > details of that package, then it's my problem! If you are a manager, and one of your (incompetent) programmers introduces dependencies on internal data structures of the compiler, which change without warning with a new version of the compiler, so that your compiler no longer works, who do you blame? Very often it is the vendor who gets the blame for introducing incompatible changes. Yes, of course you can point out from a legal point of view that it was the customer's fault, but that does not help much. After all, when Intel produced the 80188 and stole one of the "reserved" interrupts that was (mis)used by DOS, it is true that Intel was in the right, but the bottom line was that the PC Junior, and other DOS based machines, were not interested in this chip as a result. We obviously can't stop anyone changing the compiler if they want to, and introducing problems of this type, but we do like to make it clear to a user that they are taking a potentially serious step in accessing internals of the implementation, in terms of future compatibility. That is why we have the -gnatg switch, which is to be used ONLY by GNAT implementors. Of course users are free to use this switch (which among many other somewhat peculiar things, allows you to add grandchildren to Ada -- if you follow the strict style rules that are required). But as far as we are concerned, from an official point of view, users should not use -gnatg. By using a special switch, rather than casually allowing grandchildren of Ada to be compiled and recompiled, we point out to the user that this is non-standard Ada that may be incompatible with future compiler versions. Robert Dewar Ada Core Technologies -----------== Posted via Deja News, The Discussion Network ==---------- http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own