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Groups > comp.lang.forth > #1598

Re: STATE

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"BruceMcF" <agila61@netscape.net> wrote in message
news:f1988d87-facb-4c48-ad56-5f3384b1c41c@28g2000yqu.googlegroups.com...
> On Apr 29, 3:45 pm, "Rod Pemberton" <do_not_h...@noavailemail.cmm>
> wrote:
> > I don't know if it's moot whether or not one treats a low-use, or
> >  minimal-value-change, variable as a constant. E.g., spec. says one
> > thing, but common implementation differs.
>
> The statement that you were replying to was that the question of
> whether or not it [STATE] should be treated as a variable is moot
> if legacy code lock requires it to be available as a variable in any
> event, irrespective of behind the scenes implementation.
>

1) less wordy
There was no question.  That's very literal of you.  You disregarded the
meaning.  You disregarded the context.

2) more wordy
If you disregard all of the prior context regarding constant vs. variable,
and choose to restrict my statements to only the statement of Mark's
immediately prior to the first response of mine that you replied to, then,
yes, that would be correct, except for the fact that Mark's statement didn't
involve a question.  He stated his response in terms of STATE.  I took that
to be equivalent to constant vs. variable.  First, his response is
equivalent.  Second,  I assumed he expressed primarily in terms of STATE
because his earlier question seemed to express uncertainty about the
difference between variables and constant.  Unfortunately, the context
covers four messages prior to your response, not just the immediate
statement(s) to which I replied.  Constant vs. variable was what was being
discussed in this part of the thread, IMO.

> You raised the implementation details of a once-common implementation,
> that is now primarily a historical curiosity, to question whether the
> statement was right.
>

I took the conversation in this part of the thread to be choice of constant
vs. variable.   That was what Mark asked about.  That was what I replied to.
That was what he replied to, in an equivalent form IMO.  That was what I
responded to, just prior to you responding.

> That seems to be a misreading of the statement,
>

Only if you disregard earlier context ...

> If write once, read many should be a constant, write rarely, read
> often should be a value, and read and write with similar frequency
> should be a variable,
>

Who said that's what they should be?  And, why not four? five? six types?

Of course, you didn't mention other combinations of once, rarely, often,
many for read and write.  So, one could select other combinations.  Are any
of them more useful than constant or variable?  Probably not...  Is the
implementation of write once, read rarely any different than constant?  Is
write rarely, read often any different from read and write similarly?  I
agree that adding a third type - value in this case - would theoretically
solve this discussion, er... make it moot.  But, such combinations are
unneeded.  Constants are just variables that are never written to again.
So, you could ask if a low-use variable is just a constant in disguise, as
Mark did indirectly via his question about implementation of STATE.  And,
you could ask why does Forth - a language of minimalism - support constants
at all.  Clearly, there is no need for constants when one has variables.  Of
course, that denies the reality of most assembly languages which implement
constants and "variables".  Language pedants (wrongly) regard assembly as
irrelevant anyway, preferring the more abstract (simple, vague) descriptions
in the language specification.  But, a house is not built without a
foundation.  Both Forth and C were rewritten to make them work with various
assemblies of their era's.  In Forth's case, it was rewritten to work with a
HLL also.  That (assembly) is why they have variables and constants, at
least IMO.

> ... it seems like a compiler/interpreter that
> consults compiler state per word could reasonably
> implement it as a value,
>

A compiler/interpreter could reasonably implement it [STATE] as two of the
three you suggested ...  So?

> [SNIP]


Rod Pemberton

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STATE MarkWills <markrobertwills@yahoo.co.uk> - 2011-04-27 12:41 -0700
  Re: STATE Alex McDonald <blog@rivadpm.com> - 2011-04-27 13:04 -0700
    Re: STATE MarkWills <markrobertwills@yahoo.co.uk> - 2011-04-27 13:13 -0700
      Re: STATE Alex McDonald <blog@rivadpm.com> - 2011-04-27 13:45 -0700
    Re: STATE "P.M.Lawrence" <pml540114@gmail.com> - 2011-04-28 03:00 -0700
      Re: STATE Alex McDonald <blog@rivadpm.com> - 2011-04-28 04:09 -0700
        Re: STATE Alex McDonald <blog@rivadpm.com> - 2011-04-28 04:10 -0700
  Re: STATE Micke <oh2aun@gmail.com> - 2011-04-27 13:20 -0700
    Re: STATE MarkWills <markrobertwills@yahoo.co.uk> - 2011-04-27 13:26 -0700
      Re: STATE MarkWills <markrobertwills@yahoo.co.uk> - 2011-04-27 13:30 -0700
      Re: STATE Elizabeth D Rather <erather@forth.com> - 2011-04-27 11:13 -1000
        Re: STATE Elizabeth D Rather <erather@forth.com> - 2011-04-27 17:17 -1000
        Re: STATE Andrew Haley <andrew29@littlepinkcloud.invalid> - 2011-04-29 06:14 -0500
          Re: STATE Elizabeth D Rather <erather@forth.com> - 2011-04-29 08:47 -1000
            Re: STATE MarkWills <markrobertwills@yahoo.co.uk> - 2011-04-29 14:07 -0700
  Re: STATE BruceMcF <agila61@netscape.net> - 2011-04-27 19:22 -0700
  Re: STATE BruceMcF <agila61@netscape.net> - 2011-04-30 08:18 -0700
  Re: STATE BruceMcF <agila61@netscape.net> - 2011-04-30 08:26 -0700
  Re: STATE "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2011-04-30 03:24 -0400
  Re: STATE stephenXXX@mpeforth.com (Stephen Pelc) - 2011-04-30 11:41 +0000
  Re: STATE stephenXXX@mpeforth.com (Stephen Pelc) - 2011-04-30 11:53 +0000
    Re: STATE BruceMcF <agila61@netscape.net> - 2011-04-30 08:48 -0700
  Re: STATE anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2011-04-28 08:59 +0000
    Re: STATE Brad <hwfwguy@gmail.com> - 2011-04-28 08:01 -0700
      Re: STATE Andrew Haley <andrew29@littlepinkcloud.invalid> - 2011-04-28 12:16 -0500
        Re: STATE Elizabeth D Rather <erather@forth.com> - 2011-04-28 09:47 -1000
      Re: STATE BruceMcF <agila61@netscape.net> - 2011-04-28 15:56 -0700
        Re: STATE Brad <hwfwguy@gmail.com> - 2011-04-29 07:49 -0700
          Re: STATE BruceMcF <agila61@netscape.net> - 2011-04-29 11:47 -0700
      Re: STATE anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2011-04-29 17:30 +0000
    Re: STATE Albert van der Horst <albert@spenarnc.xs4all.nl> - 2011-04-28 17:47 +0000
      Re: STATE Elizabeth D Rather <erather@forth.com> - 2011-04-28 09:50 -1000
  Re: STATE "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2011-04-28 16:32 -0400
    Re: STATE MarkWills <markrobertwills@yahoo.co.uk> - 2011-04-29 02:11 -0700
      Re: STATE BruceMcF <agila61@netscape.net> - 2011-04-29 07:24 -0700
      Re: STATE "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2011-04-29 13:56 -0400
        Re: STATE BruceMcF <agila61@netscape.net> - 2011-04-29 11:44 -0700
          Re: STATE "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2011-04-29 15:45 -0400
            Re: STATE Elizabeth D Rather <erather@forth.com> - 2011-04-29 10:22 -1000
            Re: STATE BruceMcF <agila61@netscape.net> - 2011-04-29 13:31 -0700
        Re: STATE Elizabeth D Rather <erather@forth.com> - 2011-04-29 09:07 -1000

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