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Groups > comp.lang.forth > #39362

Re: unexpected +LOOP behavior

From rickman <gnuarm@gmail.com>
Newsgroups comp.lang.forth
Subject Re: unexpected +LOOP behavior
Date 2015-05-27 17:13 -0400
Organization A noiseless patient Spider
Message-ID <mk5c0b$re4$1@dont-email.me> (permalink)
References (2 earlier) <5561b9b6$0$2868$e4fe514c@news2.news.xs4all.nl> <mjsnid$99v$2@dont-email.me> <55623fa0$0$2821$e4fe514c@news2.news.xs4all.nl> <2015May27.111505@mips.complang.tuwien.ac.at> <5566258f$0$2923$e4fe514c@news2.news.xs4all.nl>

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On 5/27/2015 4:14 PM, Hans Bezemer wrote:
> Anton Ertl wrote:
>
>> This is Forth, and in Forth it's the same data type.
>
> May be you missed this QUOTE from the ANS Forth standard:
>
> "The discipline of circumscribing meaning which a program may
> assign to various combinations of bit patterns is sometimes
> called data typing. Many computer languages impose explicit data
> typing and have compilers that prevent ill-defined operations.
> Forth rarely explicitly imposes data-type restrictions. Still,
> data types implicitly do exist, and discipline is required,
> particularly if portability of programs is a goal. In Forth, it
> is incumbent upon the programmer (rather than the compiler) to
> determine that data are accurately typed."
>
> For all purposes: what a comparison operator returns is a BOOLEAN, not a
> number, not a mask, a BOOLEAN. Surprise, surprise, we AND (bit operation)
> and add (number) it.
>
> I've always stated I think it is a great lack in Forth, we don't have C
> equivalents of & and && (or | vs. ||). The only thing I can condone the use
> of a bit operator with flags if both are fully qualified flags. ANS Forth
> standard:
>
> "While Forth words which test flags accept any non-null bit pattern as true,
> there exists the concept of the well-formed flag."
>
> Followed by:
>
> " .. the following words are valid for operations on one or more flag data
> residing on the data stack: AND OR XOR INVERT"
>
> Read: one or more FLAGS - not a mixture of flags and cells or whatever.

I think you are reading what you wish to read...

6.1.0720 AND CORE
( x 1 x 2 –– x 3 )
x 3 is the bit-by-bit logical “and” of x 1 with x 2

AND is not intended to be solely a logical operator.  What are the 
boolean operators in Forth other than perhaps 0= ?


> Note you can do the same thing with 2-complement by adding "1- INVERT" for
> 1-based flags - which makes very clear we're doing some conversion. Even
> better when you put it in a word, which is named in such a way the
> operation becomes clear, e.g. >MASK.

I have discussed the issue of data typing many times in the VHDL 
language.  In VHDL strong typing is enforced and the language uses 
overloading to allow operators to be transparently defined for a variety 
of combinations of input and output types.  In such an environment 
typing helps to prevent obscure errors caused by mixing data types 
without regard to the implications.  This is primarily for the type of 
user who is not so proficient with programming and needs help.  It also 
imposes considerable overhead both in the tools to enforce the strong 
typing and in the programmer work to write code to do what is intended 
while avoiding the error reports (and the tool refusing to produce a 
design).

In the context of the Forth language where so much more is incumbent on 
the programmer to know and understand, I think data typing is much less 
useful.  I can't remember the last time I had a problem from mixing data 
types.  Forth is a language which (as is often pointed out by Hugh) 
there are few data structures and corresponding operators.  If I need to 
design my own arrays, then I think I can handle mixing of Boolean and 
integer data types.

I think you are getting wrapped around the philosophical axle on this one.

-- 

Rick

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unexpected +LOOP behavior chitselb <chitselb@gmail.com> - 2015-05-23 19:27 -0700
  Re: unexpected +LOOP behavior hughaguilar96@gmail.com - 2015-05-23 20:27 -0700
    Re: unexpected +LOOP behavior Hans Bezemer <the.beez.speaks@gmail.com> - 2015-05-24 13:44 +0200
      Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-24 10:36 -0400
        Re: unexpected +LOOP behavior Hans Bezemer <the.beez.speaks@gmail.com> - 2015-05-24 23:16 +0200
          Re: unexpected +LOOP behavior hughaguilar96@gmail.com - 2015-05-24 15:57 -0700
          Re: unexpected +LOOP behavior Bernd Paysan <bernd.paysan@gmx.de> - 2015-05-25 02:21 +0200
            Re: unexpected +LOOP behavior "Elizabeth D. Rather" <erather@forth.com> - 2015-05-24 15:21 -1000
              Re: unexpected +LOOP behavior hughaguilar96@gmail.com - 2015-05-24 19:49 -0700
            Re: unexpected +LOOP behavior hughaguilar96@gmail.com - 2015-05-24 18:22 -0700
            Re: unexpected +LOOP behavior "WJ" <w_a_x_man@yahoo.com> - 2015-05-26 17:20 +0000
              Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-26 14:15 -0400
                Re: unexpected +LOOP behavior "Elizabeth D. Rather" <erather@forth.com> - 2015-05-26 08:37 -1000
                Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-26 15:09 -0400
                Re: unexpected +LOOP behavior "Elizabeth D. Rather" <erather@forth.com> - 2015-05-26 09:19 -1000
                Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-26 17:08 -0400
                Re: unexpected +LOOP behavior chitselb <chitselb@gmail.com> - 2015-05-26 15:42 -0700
                Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-26 19:30 -0400
                Re: unexpected +LOOP behavior chitselb <chitselb@gmail.com> - 2015-05-26 17:45 -0700
                Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-26 21:33 -0400
                Re: unexpected +LOOP behavior Coos Haak <chforth@hccnet.nl> - 2015-05-27 14:08 +0200
                Re: unexpected +LOOP behavior chitselb <chitselb@gmail.com> - 2015-05-27 06:32 -0700
                Re: unexpected +LOOP behavior Coos Haak <chforth@hccnet.nl> - 2015-05-27 16:15 +0200
                Re: unexpected +LOOP behavior "Elizabeth D. Rather" <erather@forth.com> - 2015-05-26 14:32 -1000
                Re: unexpected +LOOP behavior anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-05-27 08:30 +0000
                Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-27 17:15 -0400
                Re: unexpected +LOOP behavior hughaguilar96@gmail.com - 2015-05-29 21:05 -0700
          Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-25 01:41 -0400
            Re: unexpected +LOOP behavior Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-05-24 23:26 -0700
              Re: unexpected +LOOP behavior anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-05-25 14:33 +0000
              Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-25 10:56 -0400
                Re: unexpected +LOOP behavior Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-05-25 11:28 -0700
                Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-25 14:33 -0400
                Re: unexpected +LOOP behavior hughaguilar96@gmail.com - 2015-05-25 12:57 -0700
                Re: unexpected +LOOP behavior humptydumpty <ouatubi@gmail.com> - 2015-05-25 23:01 -0700
          Re: unexpected +LOOP behavior anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-05-25 14:21 +0000
          Re: unexpected +LOOP behavior albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-05-26 23:59 +0000
          Re: unexpected +LOOP behavior anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-05-27 09:15 +0000
            Re: unexpected +LOOP behavior anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-05-27 10:06 +0000
            Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-27 12:03 -0400
              Re: unexpected +LOOP behavior anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-05-27 16:23 +0000
                Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-27 12:39 -0400
            Re: unexpected +LOOP behavior Hans Bezemer <the.beez.speaks@gmail.com> - 2015-05-27 22:14 +0200
              Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-27 17:13 -0400
                Re: unexpected +LOOP behavior Hans Bezemer <the.beez.speaks@gmail.com> - 2015-05-27 23:36 +0200
                Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-27 18:06 -0400
                Re: unexpected +LOOP behavior Hans Bezemer <the.beez.speaks@gmail.com> - 2015-05-29 10:35 +0200
                Re: unexpected +LOOP behavior "Alex McDonald" <blog@rivadpm.com> - 2015-05-29 12:16 +0100
                Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-29 09:42 -0400
                Re: unexpected +LOOP behavior Hans Bezemer <the.beez.speaks@gmail.com> - 2015-05-29 16:16 +0200
                Re: unexpected +LOOP behavior "Alex McDonald" <blog@rivadpm.com> - 2015-05-29 15:24 +0100
              Re: unexpected +LOOP behavior "Rod Pemberton" <fork@lllljunkqwer.cpm> - 2015-05-27 17:32 -0400
                Re: unexpected +LOOP behavior Coos Haak <chforth@hccnet.nl> - 2015-05-27 23:59 +0200
                Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-27 19:31 -0400
                Re: unexpected +LOOP behavior Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-05-27 23:11 -0700
              Re: unexpected +LOOP behavior "Alex McDonald" <blog@rivadpm.com> - 2015-05-28 12:21 +0100
                Re: unexpected +LOOP behavior "Alex McDonald" <blog@rivadpm.com> - 2015-05-28 12:24 +0100
                Re: unexpected +LOOP behavior Hans Bezemer <the.beez.speaks@gmail.com> - 2015-05-29 10:53 +0200
                Re: unexpected +LOOP behavior "Alex McDonald" <blog@rivadpm.com> - 2015-05-29 12:19 +0100
              Re: unexpected +LOOP behavior anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-05-29 13:51 +0000
                Re: unexpected +LOOP behavior Hans Bezemer <the.beez.speaks@gmail.com> - 2015-05-29 17:48 +0200
            Re: unexpected +LOOP behavior Bernd Paysan <bernd.paysan@gmx.de> - 2015-05-29 02:08 +0200
              Re: unexpected +LOOP behavior anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-05-29 08:25 +0000
                Re: unexpected +LOOP behavior "Alex McDonald" <blog@rivadpm.com> - 2015-05-29 12:40 +0100
                Re: unexpected +LOOP behavior anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-05-29 13:16 +0000
                Re: unexpected +LOOP behavior albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-05-29 18:43 +0000
                Re: unexpected +LOOP behavior "Alex McDonald" <blog@rivadpm.com> - 2015-05-29 20:08 +0100
                x86 tricks Lars Brinkhoff <lars.spam@nocrew.org> - 2015-06-05 09:42 +0200
                Re: x86 tricks albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-06-05 09:32 +0000
                Re: x86 tricks anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-06-05 09:40 +0000
                Re: x86 tricks albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-06-05 11:17 +0000
                Re: x86 tricks anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-06-05 15:49 +0000
                Re: x86 tricks "Alex McDonald" <blog@rivadpm.com> - 2015-06-05 17:45 +0100
                Re: x86 tricks anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-06-05 16:53 +0000
                Re: x86 tricks rickman <gnuarm@gmail.com> - 2015-06-07 13:20 -0400
                Re: x86 tricks anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-06-08 07:18 +0000
                Re: x86 tricks Bernd Paysan <bernd.paysan@gmx.de> - 2015-06-08 17:18 +0200
                Re: x86 tricks Tessa Bonting <tessa.bonting@gmail.com> - 2015-06-08 08:42 -0700
                Re: x86 tricks albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-06-06 09:47 +0000
                Re: x86 tricks anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-06-07 15:05 +0000
                Re: x86 tricks "Alex McDonald" <blog@rivadpm.com> - 2015-06-07 17:49 +0100
                Re: x86 tricks "Alex McDonald" <blog@rivadpm.com> - 2015-06-05 13:19 +0100
      Re: unexpected +LOOP behavior Mark Wills <markwills1970@gmail.com> - 2015-05-25 01:38 -0700
  Re: unexpected +LOOP behavior Michael Barry <barrym95838@yahoo.com> - 2015-05-23 21:33 -0700
    Re: unexpected +LOOP behavior hughaguilar96@gmail.com - 2015-05-23 22:10 -0700
      Re: unexpected +LOOP behavior chitselb <chitselb@gmail.com> - 2015-05-23 22:20 -0700
        Re: unexpected +LOOP behavior hughaguilar96@gmail.com - 2015-05-25 21:13 -0700
          Re: unexpected +LOOP behavior "Rod Pemberton" <fork@lllljunkqwer.cpm> - 2015-05-27 17:34 -0400
            Re: unexpected +LOOP behavior chitselb <chitselb@gmail.com> - 2015-05-27 22:04 -0700
              Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-28 01:27 -0400
                Re: unexpected +LOOP behavior "Rod Pemberton" <fork@lllljunkqwer.cpm> - 2015-05-28 03:20 -0400
                Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-28 04:13 -0400
                Re: unexpected +LOOP behavior "Rod Pemberton" <fork@lllljunkqwer.cpm> - 2015-05-29 04:23 -0400
                Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-29 11:28 -0400
                Re: unexpected +LOOP behavior "Rod Pemberton" <fork@lllljunkqwer.cpm> - 2015-05-29 18:32 -0400
                Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-29 18:53 -0400
      Re: unexpected +LOOP behavior Michael Barry <barrym95838@yahoo.com> - 2015-05-23 22:26 -0700
        Re: unexpected +LOOP behavior "Elizabeth D. Rather" <erather@forth.com> - 2015-05-23 21:37 -1000
          Re: unexpected +LOOP behavior hughaguilar96@gmail.com - 2015-05-24 10:24 -0700
            Re: unexpected +LOOP behavior "Rod Pemberton" <fork@lllljunkqwer.cpm> - 2015-05-24 20:40 -0400
            Re: unexpected +LOOP behavior Hans Bezemer <the.beez.speaks@gmail.com> - 2015-05-25 14:08 +0200
              Re: unexpected +LOOP behavior "Rod Pemberton" <fork@lllljunkqwer.cpm> - 2015-05-25 17:27 -0400
                Re: unexpected +LOOP behavior "Elizabeth D. Rather" <erather@forth.com> - 2015-05-25 14:47 -1000
                Re: unexpected +LOOP behavior "Rod Pemberton" <fork@lllljunkqwer.cpm> - 2015-05-27 17:33 -0400
            Re: unexpected +LOOP behavior Michael Barry <barrym95838@yahoo.com> - 2015-05-25 12:53 -0700
              Re: unexpected +LOOP behavior hughaguilar96@gmail.com - 2015-05-25 13:05 -0700
              Re: unexpected +LOOP behavior "Elizabeth D. Rather" <erather@forth.com> - 2015-05-25 14:49 -1000
                Re: unexpected +LOOP behavior Michael Barry <barrym95838@yahoo.com> - 2015-05-25 18:03 -0700
                Re: unexpected +LOOP behavior "Elizabeth D. Rather" <erather@forth.com> - 2015-05-25 16:44 -1000
                Re: unexpected +LOOP behavior humptydumpty <ouatubi@gmail.com> - 2015-05-25 22:56 -0700
                Re: unexpected +LOOP behavior anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-05-26 08:05 +0000
        Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-24 10:43 -0400
          Re: unexpected +LOOP behavior Michael Barry <barrym95838@yahoo.com> - 2015-05-24 08:29 -0700
            Re: unexpected +LOOP behavior anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-05-24 15:44 +0000
              Re: unexpected +LOOP behavior Michael Barry <barrym95838@yahoo.com> - 2015-05-27 00:57 -0700
              Re: unexpected +LOOP behavior chitselb <chitselb@gmail.com> - 2015-06-05 13:11 -0700
                Re: unexpected +LOOP behavior "Elizabeth D. Rather" <erather@forth.com> - 2015-06-05 12:24 -1000
                Re: unexpected +LOOP behavior JennyB <jennybrien@googlemail.com> - 2015-06-06 13:29 -0700
                Re: unexpected +LOOP behavior anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-06-07 14:56 +0000
                Re: unexpected +LOOP behavior "Elizabeth D. Rather" <erather@forth.com> - 2015-06-07 10:38 -1000
                Re: unexpected +LOOP behavior anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-06-08 08:08 +0000
        Re: unexpected +LOOP behavior hughaguilar96@gmail.com - 2015-05-24 10:01 -0700
      Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-24 10:40 -0400
        Re: unexpected +LOOP behavior hughaguilar96@gmail.com - 2015-05-24 11:29 -0700
          Re: unexpected +LOOP behavior "Alex McDonald" <blog@rivadpm.com> - 2015-05-25 09:51 -0700
            Re: unexpected +LOOP behavior hughaguilar96@gmail.com - 2015-05-25 10:44 -0700
              Re: unexpected +LOOP behavior "Alex McDonald" <blog@rivadpm.com> - 2015-05-25 12:34 -0700
                Re: unexpected +LOOP behavior hughaguilar96@gmail.com - 2015-05-25 12:59 -0700
  unexpected +LOOP behavior Mark Wills <markwills1970@gmail.com> - 2015-05-24 01:39 -0700
    Re: unexpected +LOOP behavior Coos Haak <chforth@hccnet.nl> - 2015-05-24 14:46 +0200
      Re: unexpected +LOOP behavior Mark Wills <markwills1970@gmail.com> - 2015-05-25 01:17 -0700
    Re: unexpected +LOOP behavior "Rod Pemberton" <fork@lllljunkqwer.cpm> - 2015-05-24 20:48 -0400
      Re: unexpected +LOOP behavior hughaguilar96@gmail.com - 2015-05-24 18:15 -0700
      Re: unexpected +LOOP behavior anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-05-25 12:35 +0000
        Re: unexpected +LOOP behavior "Rod Pemberton" <fork@lllljunkqwer.cpm> - 2015-05-25 17:27 -0400
          Re: unexpected +LOOP behavior rickman <gnuarm@gmail.com> - 2015-05-25 18:16 -0400
            Re: unexpected +LOOP behavior chitselb <chitselb@gmail.com> - 2015-05-25 16:17 -0700
              Re: unexpected +LOOP behavior chitselb <chitselb@gmail.com> - 2015-05-25 17:16 -0700
                Re: unexpected +LOOP behavior Michael Barry <barrym95838@yahoo.com> - 2015-05-25 17:50 -0700
                Re: unexpected +LOOP behavior chitselb <chitselb@gmail.com> - 2015-05-25 18:47 -0700
              Re: unexpected +LOOP behavior Michael Barry <barrym95838@yahoo.com> - 2015-05-25 20:01 -0700
                Re: unexpected +LOOP behavior chitselb <chitselb@gmail.com> - 2015-05-25 20:29 -0700
                Re: unexpected +LOOP behavior chitselb <chitselb@gmail.com> - 2015-05-25 20:32 -0700
              Re: unexpected +LOOP behavior anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-05-26 08:03 +0000
                Re: unexpected +LOOP behavior Mark Wills <markwills1970@gmail.com> - 2015-05-26 01:10 -0700
                Re: unexpected +LOOP behavior Michael Barry <barrym95838@yahoo.com> - 2015-05-26 22:31 -0700
                Re: unexpected +LOOP behavior Michael Barry <barrym95838@yahoo.com> - 2015-05-26 20:07 -0700
                Re: unexpected +LOOP behavior chitselb <chitselb@gmail.com> - 2015-05-26 20:20 -0700
                Re: unexpected +LOOP behavior Michael Barry <barrym95838@yahoo.com> - 2015-05-26 22:00 -0700
                Re: unexpected +LOOP behavior chitselb <chitselb@gmail.com> - 2015-05-27 02:41 -0700
  Re: unexpected +LOOP behavior anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-05-24 14:06 +0000

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