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|Date: Tue, 04 Mar 1997 11:01:59 +0100
|From: [log in to unmask] (Hans Aberg)
|Subject: Re: Shortref mechanism
|To: LaTeX3 project <[log in to unmask]>
|Cc: "Randolph J. Herber" <[log in to unmask]>

|"Randolph J. Herber" <[log in to unmask]> wrote:

|>|>|>        Please. would you use the proper nomenclature?

|>|>|>        The pairing from your improper nomenclature to what I believe
|>|>|>        is the pertinent nomenclature for what you are attempting to
|>|>|>        discuss is:

|>|>|>                deterministic           ==>             context free
|>|>|>                non-deterministic       ==>             context sensitive

|>|  I get a lot of (very long) letters of this kind, demanding that I should
|>|use this or other terminology.

|>        Ipse dixit.

        [Latin, ``he said it himself.'']

|>|  I have an old book, "Compilers", by Robin Hunter, that on page 40 defines
|>|the  notions "nondetermistic/deterministic parser" as whether of one can go
|>|back on the decision in the parsing process, or not. This is what I mean.

        [bibliography deleted]

|>|  On page 231, a "context sensitive parser" is described as a method to
|>|handle a attribute grammars, and the like. This is not what I have in mind.

|>        This refers to a parser.  I had been refering to context free
|>        languages and grammars.  ``Attribute grammars'' are concerned
|>        with semantics.  At the level of semantics all compiler and
|>        interpreters which process meaning, which attribute grammers
|>        must, must be context sensitive.

|>|  Otherwise, I do not understand how this or other terminology can solve
|>|the problems discussed here.

|>        It _may_ help solve problems in communication.

|  Perhaps the terminology varies.

        Yes, perhaps, the terminology varies.  I indicated that some
        did use ``non-deterministic'' to refer to a parser take used
        a stack machine architecture.

|  (The book by Aho et al does not have this terminology in their index.

        The Aho books, there are two in the list, both used either or
        both ``context free grammar'' or ``context sensitive grammar.''

        To be fair to you if I found a reference to ``deterministic''
        or ``non-deterministic'' whether the referent were a grammar, a
        language or an automaton, then I added a note at the bottom
        of the bibliography.

        I would say that there is sufficient evidence to say that a
        few of the authors used the words ``deterministic'' or
        ``non-deterministic'' in a manner that would support your
        meaning of a parser that back-tracks or has a stack-archtecture.

        The majority of the books did not so use those words; at least
        not in the indices.

|Is this long list really a reference list, or just a compiling of a long list
|of books in an attempt to impress?)

        I own and have read through those books.  When I sent that message,
        it was just after midnight.  My regular employment is daytime.  I
        sent the message from home while logged into a machine at work.  I
        have used those books over approximately the last three decades to
        better understand the compilation process and how to write compilers.
        I have used them to write several small compilers at work. In that
        sense the list is a reference list.  In the sense of attempting to
        demonstrate that the usual terminology in the computer computer
        field is ``context free'' or ``context sensitive,'' one might say
        that the list is also intended to impress.

        Another reason for citing a large number of books was to show
        that the terminology has not changed sigificantly in the
        approximately last three decades.

|  Otherwise, it is certainly not appropriate that some like Mr. Randolph J.
|Herber acting terminology police, telling people to use whatever
|terminology he decides is correct. This is common theme in his letters,
|telling others what to do: He decides what problems Frank Mittelbach has --
|I thought this was something Frank Mittelbach should decide. I say that
|this is the terminology I use, and this is from this or that book, and Mr.
|Randolph J. Herber says, without looking into the book, that this is not
|what it says, it says what he makes it up to say.
|  And so on...

I asked you to use the usual, proper terminology.

I will accept ``I say that this is the terminology I use'' as your
answer.  I will try to remember what meaning you have assigned to
this terminology.  I do know how successful I will be.

As an aside, this reminds me of Lewis Carroll's Thrugh the Looking Glass:

  "When I use a word," Humpty Dumpty said, in a rather scornful tone, "it means
  just what I choose it to mean - neither more nor less."
  "The question is," said Alice, "whether you can make words mean so many
  different things."
  "The question is," said Humpty Dumpty, "which is to be master - that's all."

Whom else, besides you, in this mailing list did I ask to do something,
let alone, demand to do something?  I may have forgotten or overlooked
someone or something.

What letters, other than this sequence of terminology, are you refering
to?  As far as I can determine my only other posting in this mailing list
was, in its entirely, less my signature block is:

"
Re: milliard

It is used in Russian.
"


Quoting myself from my just previous message in this sequence:

"
|>|>        Please. would you use the proper nomenclature?

                ...

        Your reference, Robin Hunter, probably used the phrase
                                      ^^^^^^^^ [emphasis added]
        ``deterministic grammar'' in the sense of being unambiguous.
        This is separate from whether the grammar is context sensitive.
        It is possible for a context sensitive grammar to be ambiguous.
"

I clearly labeled my expression as being a conjecture.  I did not claim
to have read your reference.  The three sources that I had which used
the phrase ``deterministic grammar'' did use that phrase in the sense
of ``unambiguous grammar.''  I do not feel that it is unreasonable for
me to conjecture that your reference may have also so used the phrase.

Since it is a conjecture, it is easily refuted by quoting enough context
to enable us to see that I erred in my conjecture.  You would not have
been out of place simply to say how your reference did use that phrase.

Quoting myself from a previous message in this sequence:

"
        I believe that Frank Mittelbach's point and position (not
        ``problem,'' as you say) is that changing TeX from a context
        free to a context sensitive syntax (grammar, if you wish)
        is too large of a change to be considered.
"

        I stated what I believed Frank Mittelbach's position to be.
        Neither he nor you contradicted my belief (conjecture, if
        you please).  I would be quite happy for him to correct
        any errors in this conjecture about his point or position.

Quoting you and then myself of another previous message in this sequence:

"
|  But this does not solve Frank Mittelbach's problem, as he pointed out.

        Unless you consider Frank Mittelbach's lack of interest in
        redesigning or reimplementing or a lack of resources to redesign
        and reimplement TeX's syntax processing as ``Frank Mittelbach's
        problem,'' Frank Mittelbach does not have a problem here.  I do
        not have a problem here; computer languages are a major portion
        of my education and work.
"

You are the one who refered to ``Frank Mittelbach's problem''.

Frank Mittelbach himself stated a lack of interest in redesigning or
reimplementing or a lack of resources to redesign and reimplement
TeX's syntax processing.  I conjectured that you may have considered
Frank's statement as being ``Frank Mittelbach's problem.''

What do you consider ``Frank Mittelbach's problem'' to be?

  If Mr. Randolph J. Herber is so good at these things, why does he not sit
|down and knock out some parsers written in TeX, so one can see what he can
|do?

1. I may be good at programming generally and I may have had considerably
   more experience writing compilers than most people.  But, neither
   statement means that I am good at writing in the TeX computer language.

   Nor does it mean that I know everything about programming in general
   nor about compiler writing specifically.  I do not believe that any
   one can make that claim.

   I do feel that I have had sufficient education and experience to
   have an expert's knowledge of the terminology of mathematical
   automata theory and of computer language parsing.

2. In fact, I deny that I am good at writing in the TeX computer language
   at the level level of implementing new packages and facilities.

3. Please reduce my ignorance, what, including parsers, have you
   contributed to LaTeX or this mailing list?

|  Hans Aberg

Randolph J. Herber, [log in to unmask], +1 630 840 2966,
CD/OSS/CDF CDF-PK-149O Mail Stop 234
Fermilab, Kirk & Pine Rds., P.O. Box 500, Batavia, IL 60190-0500.
(Speaking for myself and not for US, US DOE, FNAL nor URA.)
(Product, trade, or service marks herein belong to their respective owners.)
N 41 50 26.3 W 88 14 54.4 and altitude 700' approximately, WGS84 datum.