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Re: Forth reinvention

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From "Rod Pemberton" <dont_use_email@xnohavenotit.cnm>
Newsgroups comp.lang.forth
Subject Re: Forth reinvention
Date Thu, 20 Feb 2014 16:16:15 -0500
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On Thu, 20 Feb 2014 09:56:59 -0500, Alex McDonald <blog@rivadpm.com> wrote:
> on 20/02/2014 10:07:32, "Rod Pemberton" wrote:
>

>> Of course, once you eliminate infix from Forth, progress towards use
>
> You mean postfix.

Yes, true, sorry.  Technically, I meant to eliminate prefix too, not
just postfix.  So, unfortunately, 'eliminate' was actually the opposite
meaning of what I meant.

>> of symbols for logical, binary, math operations, begin to use curly
>
> Forth doesn't have logical operations.
>

If that were true, there would be no need for a "well formed flag" in  
Forth.

That was debated here recently and it seems you've supported use of "well
formed flags" in other threads.

>> braces, and eliminate the work of the user keeping track of stack
>
> Forth doesn't have a block structure.

It does.

E.g., this is a block structure:

( ... singular pre-computed condition on data stack ... )
IF
   ( ... block ... )
ELSE
   ( ... block ... )
THEN

Of course, Forth is not always expressed as well formatted text,
and doesn't have to be.

All of Forth's control-flow has words to mark the beginning and
ending of each block.  This is like many other languages, but
especially block oriented scripting languages.  But, I'll
demonstrate in COBOL (a language I've never programmed BTW):

IF ( ... set of conditions ... )
THEN
    ( ... block ... )
ELSE
    ( ... block ... )
END-IF

The THEN keyword for Forth and END-IF keyword for COBOL are needed
because they're block structured.  Inherently, all programming
languages are.

Of course, in C the syntax uses braces, if the block is more
than just one statement:

if  /* conditions */
{
   /* block */
}
else
{
   /* block */
}

You can do the same thing with any other control flow too, e.g.,
DO .. LOOP , ?DO .. +LOOP , BEGIN .. AGAIN , BEGIN .. UNTIL ,
BEGIN .. WHILE .. REPEAT , Eaker's case, etc.

Basically, the curly braces mark some of the locations where
branches for assembly or binary are placed in C.  These locations
correspond to where they are used in Forth control-flow words too.
Some Forths use BRANCH and 0BRANCH or ?BRANCH to place these branches.
The keywords in C mark some of other locations just as in Forth.
The rest are escape control-flow words like UNLOOP and EXIT in
Forth or 'break', 'continue' or 'goto' in C.

Block
http://en.wikipedia.org/wiki/Block_(programming)

Control-flow
http://en.wikipedia.org/wiki/Control_flow


Rod Pemberton

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Thread

Forth reinvention dambere@web.de - 2014-02-20 01:19 -0800
  Re: Forth reinvention "Rod Pemberton" <dont_use_email@xnohavenotit.cnm> - 2014-02-20 05:07 -0500
    Re: Forth reinvention "Alex McDonald" <blog@rivadpm.com> - 2014-02-20 14:56 +0000
      Re: Forth reinvention "Rod Pemberton" <dont_use_email@xnohavenotit.cnm> - 2014-02-20 16:16 -0500
        Re: Forth reinvention "Alex McDonald" <blog@rivadpm.com> - 2014-02-20 23:25 +0000
          Re: Forth reinvention "Rod Pemberton" <dont_use_email@xnohavenotit.cnm> - 2014-02-20 20:42 -0500
            Re: Forth reinvention "Alex McDonald" <blog@rivadpm.com> - 2014-02-21 12:41 +0000
  Re: Forth reinvention Hans Bezemer <the.beez.speaks@gmail.com> - 2014-02-20 11:18 +0100
    Re: Forth reinvention dambere@web.de - 2014-02-20 02:36 -0800
      Re: Forth reinvention Hans Bezemer <the.beez.speaks@gmail.com> - 2014-02-20 17:35 +0100
        Re: Forth reinvention dambere@web.de - 2014-02-20 11:34 -0800
          Re: Forth reinvention "Elizabeth D. Rather" <erather@forth.com> - 2014-02-20 09:53 -1000
          Re: Forth reinvention Paul Rubin <no.email@nospam.invalid> - 2014-02-20 12:23 -0800
            Re: Forth reinvention dambere@web.de - 2014-02-20 14:00 -0800
              Re: Forth reinvention Paul Rubin <no.email@nospam.invalid> - 2014-02-20 14:23 -0800
                Re: Forth reinvention dambere@web.de - 2014-02-22 02:21 -0800
                Re: Forth reinvention AKK <akk@nospam.org> - 2014-02-22 12:02 +0100
              Re: Forth reinvention Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-02-21 04:38 -0600
          Re: Forth reinvention Mark Wills <markrobertwills@yahoo.co.uk> - 2014-02-20 12:35 -0800
            Re: Forth reinvention Paul Rubin <no.email@nospam.invalid> - 2014-02-20 13:38 -0800
  Re: Forth reinvention m.a.m.hendrix@tue.nl - 2014-02-20 03:59 -0800
    Re: Forth reinvention "Alex McDonald" <blog@rivadpm.com> - 2014-02-20 15:11 +0000
      Re: Forth reinvention m.a.m.hendrix@tue.nl - 2014-02-20 07:41 -0800
  Re: Forth reinvention Richard Owlett <rowlett@pcnetinc.com> - 2014-02-20 06:38 -0600
    Re: Forth reinvention dambere@web.de - 2014-02-20 12:03 -0800
  Re: Forth reinvention Julian Fondren <julian.fondren@gmail.com> - 2014-02-20 07:08 -0800
  Re: Forth reinvention "Elizabeth D. Rather" <erather@forth.com> - 2014-02-20 09:37 -1000
    Re: Forth reinvention "Alex McDonald" <blog@rivadpm.com> - 2014-02-20 20:50 +0000
      Re: Forth reinvention "Elizabeth D. Rather" <erather@forth.com> - 2014-02-20 15:39 -1000
        Re: Forth reinvention albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-02-21 10:50 +0000
        Re: Forth reinvention Paul E Bennett <Paul_E.Bennett@topmail.co.uk> - 2014-02-21 11:10 +0000
          Re: Forth reinvention "Alex McDonald" <blog@rivadpm.com> - 2014-02-21 13:50 +0000
        Re: Forth reinvention Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-02-21 05:46 -0600
          Re: Forth reinvention "Alex McDonald" <blog@rivadpm.com> - 2014-02-21 12:55 +0000
          Re: Forth reinvention anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-02-21 15:11 +0000
            Re: Forth reinvention Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-02-22 09:23 -0600
        Re: Forth reinvention "Alex McDonald" <blog@rivadpm.com> - 2014-02-21 12:38 +0000
        Re: Forth reinvention anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-02-22 13:29 +0000
          Re: Forth reinvention "Elizabeth D. Rather" <erather@forth.com> - 2014-02-22 07:52 -1000
            Re: Forth reinvention "Alex McDonald" <blog@rivadpm.com> - 2014-02-22 19:06 +0000
            Re: Forth reinvention anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-02-23 13:40 +0000
    Re: Forth reinvention "Rod Pemberton" <dont_use_email@xnohavenotit.cnm> - 2014-02-20 20:40 -0500
      Re: Forth reinvention "Elizabeth D. Rather" <erather@forth.com> - 2014-02-20 18:43 -1000
        Re: Forth reinvention Hans Bezemer <the.beez.speaks@gmail.com> - 2014-02-21 13:16 +0100
      Re: Forth reinvention stephenXXX@mpeforth.com (Stephen Pelc) - 2014-02-21 10:49 +0000
    Re: Forth reinvention anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-02-21 14:50 +0000
      Re: Forth reinvention "Alex McDonald" <blog@rivadpm.com> - 2014-02-21 16:28 +0000
        Re: Forth reinvention anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-02-22 12:54 +0000
          Re: Forth reinvention "Rod Pemberton" <dont_use_email@xnohavenotit.cnm> - 2014-02-22 10:27 -0500
          Re: Forth reinvention "Alex McDonald" <blog@rivadpm.com> - 2014-02-22 17:49 +0000
      Re: Forth reinvention Bernd Paysan <bernd.paysan@gmx.de> - 2014-02-21 20:51 +0100
        Re: Forth reinvention Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-02-22 09:39 -0600
          Re: Forth reinvention Bernd Paysan <bernd.paysan@gmx.de> - 2014-02-23 02:40 +0100
            Re: Forth reinvention Paul Rubin <no.email@nospam.invalid> - 2014-02-22 19:24 -0800
              Re: Forth reinvention Bernd Paysan <bernd.paysan@gmx.de> - 2014-02-23 22:48 +0100
            Re: Forth reinvention Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-02-23 04:39 -0600
              Re: Forth reinvention Bernd Paysan <bernd.paysan@gmx.de> - 2014-02-23 22:46 +0100
                Re: Forth reinvention Paul Rubin <no.email@nospam.invalid> - 2014-02-23 14:26 -0800
                Re: Forth reinvention Bernd Paysan <bernd.paysan@gmx.de> - 2014-02-24 02:44 +0100
                Re: Forth reinvention Spam@ControlQ.com - 2014-03-03 12:43 -0500
                Re: Forth reinvention Paul Rubin <no.email@nospam.invalid> - 2014-03-03 10:06 -0800
                Re: Forth reinvention Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-02-24 03:59 -0600
  Re: Forth reinvention mike73900@gmail.com - 2014-03-03 14:04 -0800
    Re: Forth reinvention mhx@iae.nl - 2014-03-05 06:59 -0800
      Re: Forth reinvention Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2014-03-05 16:33 +0100
      Re: Forth reinvention Mark Wills <markwills1970@gmail.com> - 2014-03-05 09:08 -0800
        Re: Forth reinvention mhx@iae.nl - 2014-03-05 10:47 -0800
  Re: Forth reinvention AKK <akk@nospam.org> - 2014-03-07 07:30 +0100
    Re: Forth reinvention Lars Brinkhoff <lars.spam@nocrew.org> - 2014-03-07 07:55 +0100
    Re: Forth reinvention albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-03-07 09:29 +0000
      Re: Forth reinvention AKK <akk@nospam.org> - 2014-03-07 12:04 +0100
      Re: Forth reinvention "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-03-07 17:03 -0500
        Re: Forth reinvention Mark Wills <markwills1970@gmail.com> - 2014-03-08 05:31 -0800

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