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| From | cross@spitfire.i.gajendra.net (Dan Cross) |
|---|---|
| Newsgroups | comp.arch |
| Subject | Re: Documentation (was Re: Performance of xchg reg,reg) |
| Date | 2026-10-20 02:05 +0000 |
| Organization | PANIX Public Access Internet and UNIX, NYC |
| Message-ID | <11b6i8h$hn8$1@reader2.panix.com> (permalink) |
| References | <2026Oct13.104347@mips.complang.tuwien.ac.at> <6ad5609b.8505984@news.eternal-september.org> <11b3t5j$h7l$1@reader2.panix.com> <7tocdllvftsndin92d9q2kjf90if8dha8p@4ax.com> |
In article <7tocdllvftsndin92d9q2kjf90if8dha8p@4ax.com>,
George Neuner <gneuner2@comcast.net> wrote:
>On Mon, 19 Oct 2026 01:52:51 -0000 (UTC),
>cross@spitfire.i.gajendra.net (Dan Cross) wrote:
>
>>In article <6ad5609b.8505984@news.eternal-september.org>,
>>John Savard <quadibloc@invalid.com> wrote:
>>>On Sun, 18 Oct 2026 09:45:00 -0400, George Neuner
>>><gneuner2@comcast.net> wrote:
>>>
>>>>The problem with the original report was that they attempted with the
>>>>grammar turn [at least some kinds of] semantic errors into syntax
>>>>errors.
>>>
>>>Obviously, there's no way one can enable a compiler to flag logic
>>>errors in programs. A Turing-complete language can calculate anything,
>>>so how can it tell you that you were calculating this when you wanted
>>>to calculate that?
>>
>>With apologies, arguments like these always seem to me to miss
>>the forest for the trees a bit. Some constructs clearly violate
>>the documented semantics of e.g. a language.
>>
>>Yes, these langauges are all Turing-complete and so on, and no,
>>we cannot solve _The_ Halting Problem, in all of its glorious
>>generality. But, we can solve any number of specific halting
>>_problems_. For example, I can see that, `for (;;);` is a loop
>>that does not terminate. With enough effort, I can take that
>>down some reasonably long paths.
>>
>>So, too, one can spot a lot of logic errors. There's no reason
>>a compiler can't see this, for example:
>>
>>? if (ptr == NULL) {
>>? int v = *ptr++;
>>? *ptr = v + 10;
>>? }
>>
>>And flag it with a error: "you dereferenced a pointer right
>>after you asserted it was nil; did you invert the condition?"
>
>Absolutely compiler analysis can catch (some) semantic errors ... that
>never was in question.
Sorry, I was referring specifically to the factually incorrect
statement that "there's no way one can enable a compiler to flag
logic errors in programs," quoted above, which is flatly
incorrect.
>The problem with the *original* Algol68 report was that they tried to
>encode semantics using the syntax, the idea being that the parser then
>could catch semantic errors as syntax errors.
>
>The revised report changed direction: the syntax no longer tried to
>encode the semantics ... but it still was hard to read because the
>syntax definitions made copious /reference/ to semantics discussed in
>accompanying text.
Oophf. Sounds painful.
- Dan C.
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Performance of xchg reg,reg anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-13 08:43 +0000
Re: Performance of xchg reg,reg Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-10-14 00:23 +0000
Re: Performance of xchg reg,reg anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-14 07:00 +0000
Re: Performance of xchg reg,reg MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-10-14 22:35 +0000
Re: Performance of xchg reg,reg Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-10-14 23:07 +0000
Re: Performance of xchg reg,reg anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-15 06:05 +0000
Re: Performance of xchg reg,reg anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-15 07:06 +0000
Re: Performance of xchg reg,reg EricP <ThatWouldBeTelling@thevillage.com> - 2026-10-16 09:47 -0400
Re: Performance of xchg reg,reg anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-16 16:04 +0000
Re: Performance of xchg reg,reg Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-10-17 05:46 +0000
Re: Performance of xchg reg,reg Michael S <already5chosen@yahoo.com> - 2026-10-14 22:29 +0300
Re: Performance of xchg reg,reg "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-15 14:21 -0700
Re: Performance of xchg reg,reg Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-10-15 21:42 +0000
Re: Performance of xchg reg,reg Terje Mathisen <terje.mathisen@tmsw.no> - 2026-10-16 14:45 +0200
Re: Performance of xchg reg,reg anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-16 05:50 +0000
Re: Performance of xchg reg,reg Michael S <already5chosen@yahoo.com> - 2026-10-16 11:34 +0300
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-16 18:23 +0000
Re: Performance of xchg reg,reg scott@slp53.sl.home (Scott Lurndal) - 2026-10-16 20:48 +0000
Re: Performance of xchg reg,reg "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-16 14:28 -0700
Re: Performance of xchg reg,reg Thomas Koenig <tkoenig@netcologne.de> - 2026-10-17 09:48 +0000
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-17 02:50 +0000
Re: Performance of xchg reg,reg MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-10-17 17:11 +0000
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-17 17:31 +0000
Re: Performance of xchg reg,reg MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-10-17 19:39 +0000
Re: Performance of xchg reg,reg Michael S <already5chosen@yahoo.com> - 2026-10-17 23:20 +0300
Re: Documentation (was Re: Performance of xchg reg,reg) Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-10-17 20:54 +0000
Re: Documentation (was Re: Performance of xchg reg,reg) George Neuner <gneuner2@comcast.net> - 2026-10-18 09:45 -0400
Algol 68 (was: Documentation (was Re: Performance of xchg reg,reg)) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-18 14:08 +0000
Re: Algol 68 (was: Documentation (was Re: Performance of xchg reg,reg)) quadibloc@invalid.com (John Savard) - 2026-10-19 00:09 +0000
Re: Algol 68 (was Re: Documentation) Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-10-19 01:46 +0000
Re: Algol 68 (was Re: Documentation) quadibloc@invalid.com (John Savard) - 2026-10-21 14:15 +0000
Re: Algol 68 (was Re: Documentation) Niklas Holsti <niklas.holsti@tidorum.invalid> - 2026-10-21 18:34 +0300
Re: Algol 68 (was Re: Documentation) quadibloc@invalid.com (John Savard) - 2026-10-21 19:38 +0000
Re: Algol 68 (was Re: Documentation) aph@littlepinkcloud.invalid - 2026-10-22 09:51 +0000
Re: Algol 68 (was Re: Documentation) Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2026-10-22 14:15 -0700
Re: Algol 68 (was Re: Documentation) scott@slp53.sl.home (Scott Lurndal) - 2026-10-23 14:08 +0000
Re: PL/I, was Algol 68 (was: Documentation (was Re: Performance of xchg reg,reg)) John Levine <johnl@taugh.com> - 2026-10-19 03:24 +0000
Re: PL/I, was Algol 68 (was: Documentation (was Re: Performance of xchg reg,reg)) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-19 05:34 +0000
Re: Algol 68 Stefan Monnier <monnier@iro.umontreal.ca> - 2026-10-18 23:34 -0400
Re: Documentation (was Re: Performance of xchg reg,reg) quadibloc@invalid.com (John Savard) - 2026-10-19 00:18 +0000
Re: Documentation (was Re: Performance of xchg reg,reg) cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-19 01:52 +0000
Re: Documentation (was Re: Performance of xchg reg,reg) George Neuner <gneuner2@comcast.net> - 2026-10-19 14:50 -0400
Re: Documentation (was Re: Performance of xchg reg,reg) cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-20 02:05 +0000
Re: Algol 68 (was Re: Documentation) Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-10-19 01:54 +0000
Re: Documentation (was Re: Performance of xchg reg,reg) Thomas Koenig <tkoenig@netcologne.de> - 2026-10-19 07:44 +0000
Re: Documentation (was Re: Performance of xchg reg,reg) Stefan Monnier <monnier@iro.umontreal.ca> - 2026-10-19 12:24 -0400
Re: Documentation (was Re: Performance of xchg reg,reg) MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-10-18 17:48 +0000
Re: Performance of xchg reg,reg George Neuner <gneuner2@comcast.net> - 2026-10-18 08:59 -0400
Re: Performance of xchg reg,reg anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-18 15:08 +0000
Re: Performance of xchg reg,reg Michael S <already5chosen@yahoo.com> - 2026-10-18 18:43 +0300
Re: Performance of xchg reg,reg anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-18 16:57 +0000
Re: Performance of xchg reg,reg Michael S <already5chosen@yahoo.com> - 2026-10-18 20:47 +0300
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-18 18:07 +0000
Re: Performance of xchg reg,reg anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-18 21:04 +0000
Re: Performance of xchg reg,reg Stefan Monnier <monnier@iro.umontreal.ca> - 2026-10-18 23:43 -0400
Re: Performance of xchg reg,reg Stephen Fuld <sfuld@alumni.cmu.edu.invalid> - 2026-10-19 06:57 -0700
Re: Performance of xchg reg,reg "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-19 14:27 -0700
Re: Performance of xchg reg,reg Stefan Monnier <monnier@iro.umontreal.ca> - 2026-10-20 10:00 -0400
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-20 02:00 +0000
Re: Performance of xchg reg,reg scott@slp53.sl.home (Scott Lurndal) - 2026-10-20 14:09 +0000
Re: Performance of xchg reg,reg "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-20 16:44 -0700
Re: Performance of xchg reg,reg Stefan Monnier <monnier@iro.umontreal.ca> - 2026-10-20 10:05 -0400
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-20 19:56 +0000
Re: Performance of xchg reg,reg anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-10-22 10:54 +0000
Re: Performance of xchg reg,reg Michael S <already5chosen@yahoo.com> - 2026-10-22 22:11 +0300
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-18 17:40 +0000
Re: Performance of xchg reg,reg Michael S <already5chosen@yahoo.com> - 2026-10-18 20:54 +0300
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-18 18:25 +0000
Re: Performance of xchg reg,reg MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-10-18 18:01 +0000
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-18 17:59 +0000
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-18 17:09 +0000
Re: Performance of xchg reg,reg EricP <ThatWouldBeTelling@thevillage.com> - 2026-10-18 12:31 -0400
Re: Performance of xchg reg,reg cross@spitfire.i.gajendra.net (Dan Cross) - 2026-10-18 17:47 +0000
Re: Performance of xchg reg,reg "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-18 12:27 -0700
Re: Performance of xchg reg,reg EricP <ThatWouldBeTelling@thevillage.com> - 2026-10-19 09:38 -0400
Re: Performance of xchg reg,reg "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-19 14:08 -0700
Re: Performance of xchg reg,reg Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-10-19 21:21 +0000
Re: Performance of xchg reg,reg "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-19 14:26 -0700
Re: Performance of xchg reg,reg Joseph Seigh <jseigh_es00@xemaps.com> - 2026-10-19 19:17 -0400
Re: Performance of xchg reg,reg "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-10-19 22:41 -0700
Re: Performance of xchg reg,reg MitchAlsup <user5857@newsgrouper.org.invalid> - 2026-10-20 16:45 +0000
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