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: 103376,799e6e37c90ca633 X-Google-Attributes: gid103376,public From: Martin Dowie Subject: Re: Future Ada language revisions? Date: 1998/10/06 Message-ID: #1/1 X-Deja-AN: 398330093 X-NNTP-Posting-Host: dowie-cs.demon.co.uk:193.237.34.207 References: <6um7on$db5$1@nnrp1.dejanews.com> <6v9es0$bnv$1@nnrp1.dejanews.com> <6vdbcg$p9c$1@nnrp1.dejanews.com> <6vdg8g$16g$1@nnrp1.dejanews.com> X-Complaints-To: abuse@demon.net X-Trace: news.demon.co.uk 907694406 nnrp-09:25004 NO-IDENT dowie-cs.demon.co.uk:193.237.34.207 MIME-Version: 1.0 Newsgroups: comp.lang.ada Date: 1998-10-06T00:00:00+00:00 List-Id: In article <6vdg8g$16g$1@nnrp1.dejanews.com>, dewarr@my-dejanews.com writes >> What about exceptions raised by a called subprogram *called by* this >> function? How about those that are raised within a rendezvous? What if said >> exception isn't visible in the package specification where this declaration >> has to be placed? How is the compiler to know that I even *want* an exception >> handled? Do you want every unit that calls Put_Line to spit out warnings >> about missing explicit handlers for use_error and mode_error? > > >Right exactly. So that observation is the *starting* point for trying to >design a reasonable facility. Obviously the first thought that all exceptions >should be mentioned is quite wrong. So now the question becomes, can we find >some other form of expression that is still useful, without being a useless >pain in the neck. > >Various partial solutions have been suggested, but none proved satisfactory. sorry, i didn't mean to imply that every exception had to be named in the spec! the compile time check when compiling the subprogram body could be limited to ensuring that those explicitly mentioned, are explicitly raised (or something more sensible than i can come up with!). for those that aren't named (e.g. out of scope) the extension could include an 'or others' declaration to specify that other exceptions can be raised. > This is of course a very old idea, one that has been introduced in > some languages, and was of course discussed in detail during the Ada > 83 and Ada 95 designs. Again, it is clear what the arguments are on > both sides of this issue, and I don't see anything new coming up. > There was some sentiment for revisiting this during the Ada 95 design, > but not much. i tried hunting down anything about this topic in DN (excruciating!) and managed to download a few 100Ks of the "preliminary findings of the Ada 9X Requirements Team " (all i could find) but there didn't seem to be anything about this type of proposal. -- Martin Dowie