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=unavailable autolearn_force=no version=3.4.4 X-Received: by 2002:ac8:71ca:: with SMTP id i10mr4961873qtp.149.1569357623601; Tue, 24 Sep 2019 13:40:23 -0700 (PDT) X-Received: by 2002:a9d:3b26:: with SMTP id z35mr3406199otb.182.1569357623389; Tue, 24 Sep 2019 13:40:23 -0700 (PDT) Path: eternal-september.org!reader01.eternal-september.org!feeder.eternal-september.org!weretis.net!feeder6.news.weretis.net!feeder.usenetexpress.com!feeder-in1.iad1.usenetexpress.com!border1.nntp.dca1.giganews.com!nntp.giganews.com!o24no5707595qtl.0!news-out.google.com!q23ni320qtl.1!nntp.google.com!o24no5707592qtl.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Tue, 24 Sep 2019 13:40:23 -0700 (PDT) In-Reply-To: Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=47.185.223.245; posting-account=zwxLlwoAAAChLBU7oraRzNDnqQYkYbpo NNTP-Posting-Host: 47.185.223.245 References: <5edf39fb-169a-463a-b28e-ece1d3b553e0@googlegroups.com> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: Subject: Re: Implementing Rust's borrow checked pointers From: Optikos Injection-Date: Tue, 24 Sep 2019 20:40:23 +0000 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Xref: reader01.eternal-september.org comp.lang.ada:57188 Date: 2019-09-24T13:40:23-07:00 List-Id: On Tuesday, September 24, 2019 at 3:31:15 PM UTC-5, Keith Thompson wrote: > Optikos writes: > > On Tuesday, September 24, 2019 at 2:13:33 PM UTC-5, Keith Thompson wrot= e: > >> Lucretia writes: > [...] > >> > Yes, the compiler would raise that exception at compile time. This > >> > idea that all exceptions are raised at runtime is false and you shou= ld > >> > check the AARM. > >>=20 > >> Can you provide a specific citation? > >>=20 > >> Certainly a compiler can diagnose an error at compile time, but I've > >> never heard that referred to as an "exception". And a compiler can > >> generate code that unconditionally raises an exception, but that code = is > >> executed at run time. > >>=20 > >> (I've seen compile-time exceptions, but they were compiler bugs, not > >> diagnostics for the program being compiled.) > > > > Keith, I already did in a prior posting above, but you apparently > > blocked me, so your loss. >=20 > I have not blocked you. It's entirely possible that I missed your > earlier article (I don't follow this newsgroup all that closely), > or that I read it but didn't think it supported the assertion. >=20 > > Here is the answer to your question again > > for all other readers: =C2=A71.1.5 Classification of =E2=80=A2Errors = =E2=80=9CIf such an > > =E2=80=A2error=E2=80=A2 situation is certain to arise in every executio= n of a > > construct, then an implementation is =E2=80=A2=E2=80=A2=E2=80=A2allowed= (although not > > required)=E2=80=A2=E2=80=A2=E2=80=A2 to report this fact at =E2=80=A2co= mpilation=E2=80=A2 time.=E2=80=9D >=20 > That doesn't describe raising an exception at compilation time. > It describes (optionally) *reporting* at compilation time that an > exception is certain to be raised at run time. >=20 > Again, the claim (from Lucretia, not from you) was: >=20 > Yes, the compiler would raise that exception at compile > time. This idea that all exceptions are raised at runtime is > false and you should check the AARM. I already answered that in my 9:08AM reply today. I demonstrated via exten= sive quotation from AARM that Luke utilized the incorrect term-of-art. Acc= ording to the AARM as written, Luke meant =E2=80=9Cerror=E2=80=9D (as quote= d from AARM) when he wrote =E2=80=9Cexception=E2=80=9D (as quoted from c.l.= a). With a relatively minor change from Luke's =E2=80=9Craise exception=E2= =80=9D to emit error message at compile-time, Luke's statement is otherwise= correct. > Printing a warning message is not raising an exception.