Re: specifying semantics, was Formatting of Language LRMs

From	George Neuner <gneuner2@comcast.net>
Newsgroups	comp.compilers
Subject	Re: specifying semantics, was Formatting of Language LRMs
Date	2014-06-29 07:56 -0400
Organization	A noiseless patient Spider
Message-ID	<14-06-030@comp.compilers> (permalink)
References	<14-06-010@comp.compilers> <14-06-023@comp.compilers> <14-06-025@comp.compilers> <14-06-027@comp.compilers>

Show all headers | View raw

Hi Ivan,

On Sat, 28 Jun 2014 12:25:18 -0700, Ivan Godard <ivan@ootbcomp.com>
wrote:

>Where would you place VWG on the operational/denotational/axiomatic
>spectrum?

Denotational.

Technically any grammar formalism is a denotational description of the
syntax of the accepted/generated language.  But I think what you
really may be asking is whether a vW-grammar also is a semantic
description of the language it describes.

The only place I have seen a 2 level grammar used was in the original
Algol68 report.  Despite the inclusion of semantically meaningful
terms like "inseparable" and "strongly", etc., in actuality the vW
grammar in the report was used only for syntax specification. Language
semantics were not described *using* the formalism but rather were
given by accompanying text and only were *referenced* by the
formalism.

[Quickly reviewing the reports I noticed that the revised report
adopted a different (though equally dense) 2 level grammar "to make
its study easier for the uninitiated reader".  Honestly, I don't see
how the "NEST" grammar was any improvement on the vW.]

At the most basic, any grammar imparts some (very limited) semantics
to the described language by constraining[*] the symbolic alphabet and
the set of strings that are to be considered valid.  However, the
meaning of those strings is knowable only to an observer/manipulator at
a level higher than the grammar that describes them.

[*] Even though the set of valid strings may, in fact, be infinite,
owing to constraints the set must be countably infinite and therefore
(theoretically) enumerable. 8-)

Of course, 2-level grammars like vW can be shown to be Turing Complete
- so in theory one could describe Yet Another Grammar which, in turn,
could be used to describe both the syntax and denotation semantics of
Yet Another Language.  I can imagine that the YAG is some sort of a
declarative programming language in its own right and the YAL is a
program "written" in YAG which is (or generates) the compiler for YAL.

Ouch!  I've just gotten a meta-circular headache!
George

Thread

Formatting of Language LRMs Seima Rao <seimarao@gmail.com> - 2014-06-17 16:54 +0530
  Re: Formatting of Language LRMs "lpsantil@gmail.com" <lpsantil@gmail.com> - 2014-06-20 10:10 -0700
    Re: Formatting of Language LRMs glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-08-03 04:37 +0000
  Re: Formatting of Language LRMs Ivan Godard <ivan@ootbcomp.com> - 2014-06-20 12:09 -0700
    Re: Formatting of Language LRMs glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-06-21 02:27 +0000
    Re: Formatting of Language LRMs Kaz Kylheku <kaz@kylheku.com> - 2014-06-21 03:09 +0000
    Re: Formatting of Language LRMs Joshua Cranmer 🐧 <Pidgeot18@verizon.net.invalid> - 2014-06-22 21:12 -0500
      Re: VWG and K, was Formatting of Language LRMs Ivan Godard <ivan@ootbcomp.com> - 2014-06-22 21:47 -0700
      RE: Formatting of Language LRMs "Costello, Roger L." <costello@mitre.org> - 2014-07-03 09:06 +0000
        Re: Formatting of Language LRMs Ivan Godard <ivan@ootbcomp.com> - 2014-07-03 22:30 -0700
          Re: syntax checkers, was Formatting of Language LRMs glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-07-04 17:35 +0000
          Re: executable semantics, was Formatting of Language LRMs wclodius@earthlink.net (William Clodius) - 2014-07-04 15:53 -0600
  Re: specifying semantics, was Formatting of Language LRMs seimarao@gmail.com - 2014-06-24 02:19 -0700
    Re: specifying semantics, was Formatting of Language LRMs "lpsantil@gmail.com" <lpsantil@gmail.com> - 2014-06-24 13:12 -0700
    Re: specifying semantics, was Formatting of Language LRMs George Neuner <gneuner2@comcast.net> - 2014-06-26 00:54 -0400
      Re: specifying semantics, was Formatting of Language LRMs Andy Walker <news@cuboid.co.uk> - 2014-06-28 20:10 +0100
        Re: specifying semantics, was Formatting of Language LRMs George Neuner <gneuner2@comcast.net> - 2014-06-28 22:43 -0400
          Re: BNF, was specifying semantics wclodius@earthlink.net (William Clodius) - 2014-06-30 22:00 -0600
      Re: specifying semantics, was Formatting of Language LRMs Ivan Godard <ivan@ootbcomp.com> - 2014-06-28 12:25 -0700
        Re: specifying semantics, was Formatting of Language LRMs Andy Walker <news@cuboid.co.uk> - 2014-06-29 11:19 +0100
        Re: specifying semantics, was Formatting of Language LRMs George Neuner <gneuner2@comcast.net> - 2014-06-29 07:56 -0400
          Re: specifying semantics, was Formatting of Language LRMs Ivan Godard <ivan@ootbcomp.com> - 2014-06-29 11:49 -0700
            Re: specifying semantics, was Formatting of Language LRMs Gene Wirchenko <genew@telus.net> - 2014-06-30 18:09 -0700
              Re: specifying semantics, was Formatting of Language LRMs Ivan Godard <ivan@ootbcomp.com> - 2014-06-30 20:53 -0700
                Re: Algol history, was specifying semantics anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-07-03 11:51 +0000
                Re: Algol history, was specifying semantics Ivan Godard <ivan@ootbcomp.com> - 2014-07-03 22:20 -0700
                Re: Algol history, was specifying semantics wclodius@earthlink.net (William Clodius) - 2014-07-04 15:52 -0600
                Re: Algol history, was specifying semantics glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-07-07 05:49 +0000
                Re: Algol history, was specifying semantics Ivan Godard <ivan@ootbcomp.com> - 2014-07-07 10:48 -0700
                Re: Algol history, was specifying semantics glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-07-07 19:49 +0000
                Re: Algol history, was specifying semantics glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-07-07 19:43 +0000
                Re: specifying semantics, was Formatting of Language LRMs Gene Wirchenko <genew@telus.net> - 2014-07-03 21:44 -0700
            Re: specifying semantics, was Formatting of Language LRMs anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-07-02 09:51 +0000
              Re: specifying semantics, was Formatting of Language LRMs Stefan Monnier <monnier@iro.umontreal.ca> - 2014-07-03 10:15 -0400
                Re: specifying semantics, was Formatting of Language LRMs glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-07-04 06:08 +0000
                Re: specifying semantics, was Formatting of Language LRMs Hans-Peter Diettrich <DrDiettrich1@aol.com> - 2014-07-04 08:51 +0200
                Re: Parsing Fortran, was specifying semantics glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-07-04 17:53 +0000
                Re: Parsing Fortran, was specifying semantics wclodius@earthlink.net (William Clodius) - 2014-07-04 15:57 -0600
  Re: Formatting of Language LRMs mertesthomas@gmail.com - 2014-06-30 12:04 -0700
  Re: Formatting of Language LRMs federation2005@netzero.com - 2014-07-28 17:55 -0700
    Re: Formatting of Language LRMs federation2005@netzero.com - 2014-08-01 14:58 -0700

csiph-web