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 10.107.16.82 with SMTP id y79mr16876631ioi.103.1523245830753; Sun, 08 Apr 2018 20:50:30 -0700 (PDT) X-Received: by 2002:a9d:29d2:: with SMTP id g18-v6mr2008944otd.5.1523245830449; Sun, 08 Apr 2018 20:50:30 -0700 (PDT) Path: eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!feeder.eternal-september.org!news.unit0.net!peer01.am4!peer.am4.highwinds-media.com!peer03.iad!feed-me.highwinds-media.com!news.highwinds-media.com!u184-v6no1754726ita.0!news-out.google.com!u64-v6ni3316itb.0!nntp.google.com!u184-v6no1754722ita.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Sun, 8 Apr 2018 20:50:30 -0700 (PDT) In-Reply-To: Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=47.185.233.194; posting-account=zwxLlwoAAAChLBU7oraRzNDnqQYkYbpo NNTP-Posting-Host: 47.185.233.194 References: <1b44444f-c1b3-414e-84fb-8798961487c3@googlegroups.com> <62ee0aac-49da-4925-b9aa-a16695b3fc45@googlegroups.com> <9879872e-c18a-4667-afe5-41ce0f54559f@googlegroups.com> <80db2d05-744f-4201-ba1b-4436f8040491@googlegroups.com> <59f9ab6d-d6ba-45ff-a6f0-c5699983d9e8@googlegroups.com> <1a390e22-f49f-4028-8e58-ca4d0f51e4b6@googlegroups.com> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: <8fca2fed-2721-48dc-95e5-5b98e7c1fa70@googlegroups.com> Subject: Re: Interesting article on ARG work From: "Dan'l Miller" Injection-Date: Mon, 09 Apr 2018 03:50:30 +0000 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Received-Bytes: 5180 X-Received-Body-CRC: 2848863722 Xref: reader02.eternal-september.org comp.lang.ada:51404 Date: 2018-04-08T20:50:30-07:00 List-Id: On Sunday, April 8, 2018 at 3:09:55 PM UTC-5, Dmitry A. Kazakov wrote: > On 2018-04-08 21:48, Dan'l Miller wrote: > > On Sunday, April 8, 2018 at 2:46:15 AM UTC-5, Dmitry A. Kazakov wrote: > >> if Foo then > >> @ Bar; > >> @ end if; > >> @ if Boo then > >> Baz; > >> end if; > >> > >> would not be legal either. > >=20 > > Where =E2=90=A0 is the ASCII/ISO646 space character (presented as a gra= phical character for visualization herein), > >=20 > > if Foo then > > =E2=90=A0 Bar; > > =E2=90=A0 end if; > > =E2=90=A0 if Boo then > > Baz; > > end if; > >=20 > > and > >=20 > > if Foo then > > -- Bar; > > -- end if; > > -- if Boo then > > Baz; > > end if; > >=20 > > both are legal Ada statements, spurious and non sequitur evocations of = the ARM notwithstanding. > >=20 > > In general, Dmitry, you seem to not understand that a generalized left-= right (GLR) parser would parse both sides of the @ concurrently. Your enti= re premise is that it is impossible to parse both presence and absence of @= at the same time. In GLR, you are incorrect. >=20 > No, I don't understand what are you trying to say or how is it related=20 > to the issue discussed. I am saying that your insistence on conformance of the extent of the @-code= to any portion of the BNF (or anything else) in the ARM is 100% misguided,= tantamount to being a troller fisherman. I am saying that you are 100% incorrect that only the presence or only the = absence of the @-code will be compiled in the most-exemplary implementation= , leaving the other uncompiled variant to bit-rot uncompiled for extended p= eriods of time. I am saying that you sure appear to be quite ignorant of G= LR parsers' ability to parse both the presence and absence of the @-code = =E2=80=A2=E2=80=A2concurrently in the same invocation=E2=80=A2=E2=80=A2 of = the compiler in O(n) time in this case (because the @ mechanism does not su= ffer combinatorial explosion of, say, C preprocessor's arbitrarily-nested #= if...#endif constructs, which in their worst case can evoke GLR parsers' O(= n=C2=B3)-growth time on top of the combinatorial explosion's growth rate). = GLR parsers accomplish this by forking/bifurcating the push-down automata'= s reduced-production stack before rejoining the forks into traditional LR m= ode: one fork of the bifurcated reduced-production stack for =E2=80=A2pres= ence=E2=80=A2 of the @-code and one fork of the bifurcated reduced-producti= on stack for the =E2=80=A2absence=E2=80=A2 of the @-code. I am saying that= you apparently have not even read the Wikipedia article on GLR parsers: h= ttps://en.wikipedia.org/wiki/GLR_parser I am saying that nearly everything that you have said among your multiple r= eplies to Randy's @-code is hogwash and horse-hooey. Perhaps. Every. Wor= d. Of. It. (especially regarding your pontifications in the large for al= l possible implementations that no well-oiled-machine spectacular implement= ation of the @-code is possible; perhaps you might hit the nail on the head= on a subpoint here and there regarding some less-than-exemplary implementa= tion).