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,df854b5838c3e14 X-Google-Attributes: gid103376,public From: bobduff@world.std.com (Robert A Duff) Subject: Re: Gripe about Ada, rep specs that won't. Date: 1996/03/24 Message-ID: #1/1 X-Deja-AN: 144487903 references: <00001a73+00002504@msn.com> organization: The World Public Access UNIX, Brookline, MA newsgroups: comp.lang.ada Date: 1996-03-24T00:00:00+00:00 List-Id: In article , Robert Dewar wrote: >As an example, there is no requirement to accept 'size on a record AT ALL, >as far as I can tell, which means that: > > type x is record > a,b : Boolean; > end record; > > pragma Pack (X); My reading of 13.2(8) is that the implementation has to pack this into 2 bits. For example, if x is used as a component of another packed record, or a packed array, then the size of the component will be 2 bits. >could make x'size 8, and the clause > > for x'size use 2; > >is allowed to be rejected. Maybe -- the 'Size wording is rather less than perfect. Perhaps the ARG should rule on this. In any case, whether or not the 'Size is supported, I think 13.2(8) says the thing has to fit in two bits. >Now I think this will turn out to be a mostly theoretical consideration, >since real Ada compilers will be designed to be useful, rather than >meet the minimum requirements. For a feature that is dealing with low level stuff, and is therefore at least somewhat unportable anyway, the above is good enough for me -- if enough people want a given sort of rep clause enough, then vendors will support it. In fact, I don't even care whether it's "simple" in the underlying hardware -- what matters is the cost/benefit. Keep in mind that my lax view on this applies only to chapter-13-ish stuff -- the high level features of the language are different -- they should be standardized more strictly. - Bob