Re: revisiting a prgramming problem

From	Gerry Jackson <spam@qlikz.org>
Newsgroups	comp.lang.forth
Subject	Re: revisiting a prgramming problem
Date	2014-10-22 21:57 +0100
Organization	A noiseless patient Spider
Message-ID	<m295o0$tth$1@dont-email.me> (permalink)
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On 22/10/2014 07:26, Paul Rubin wrote:
> "Rod Pemberton" <buzzoff@nonamewhichexists.cmm> writes:
>> : 2SORT 2DUP < IF SWAP THEN ;
>> : 2MAX 2SORT ROT 2SORT DROP ;
>> : SQSUM 2MAX DUP * SWAP DUP * + ;
>> It doesn't need the return stack.  And, you might be able to work MAX
>> in for one of the 2SORTS that way
>
> MAX of course wraps a conditional

'Of course'? In practice you are almost certainly correct but MAX (and 
MIN) can be implemented in ANS Forth without an IF. For amusement I 
wondered how many ways it could be done and came up with the following, 
all using a boolean as a number e.g.

: max 2dup < 1+ pick nip nip ;

: max 2dup > 1+ roll drop ;

: selxt does> cell+ swap cells + @ execute ;
create minmax ' drop , ' nip , selxt
: max 2dup > minmax ;
: min 2dup < minmax ;

: max s" swap drop" 2over > -4 * /string evaluate ;

2variable n2n1
: max 2dup n2n1 2! > negate cells n2n1 + @ ;

Any more?

I'm not saying these are better than the usual definition just 
demonstrating what's possible.

It's worth looking at chapter 8 of Thinking Forth.

-- 
Gerry

Thread

revisiting a prgramming problem gavino_himself <visploveslisp@gmail.com> - 2014-10-14 15:55 -0700
  Re: revisiting a prgramming problem hughaguilar96@yahoo.com - 2014-10-14 18:52 -0700
    Re: revisiting a prgramming problem Hans Bezemer <the.beez.speaks@gmail.com> - 2014-10-21 17:58 +0200
      Re: revisiting a prgramming problem Paul Rubin <no.email@nospam.invalid> - 2014-10-21 09:09 -0700
        Re: revisiting a prgramming problem Hans Bezemer <the.beez.speaks@gmail.com> - 2014-10-21 22:18 +0200
          Re: revisiting a prgramming problem rickman <gnuarm@gmail.com> - 2014-10-23 15:44 -0400
            Re: revisiting a prgramming problem "Rod Pemberton" <buzzoff@nonamewhichexists.cmm> - 2014-10-23 17:01 -0400
            Re: revisiting a prgramming problem the_gavino_himself <visphatesjava@gmail.com> - 2014-11-08 21:33 -0800
              Re: revisiting a prgramming problem rickman <gnuarm@gmail.com> - 2014-11-29 20:40 -0500
                Re: revisiting a prgramming problem the_gavino_himself <visphatesjava@gmail.com> - 2014-12-01 22:43 -0800
                Re: revisiting a prgramming problem rickman <gnuarm@gmail.com> - 2014-12-02 02:47 -0500
                Re: revisiting a prgramming problem Paul E Bennett <Paul_E.Bennett@topmail.co.uk> - 2014-12-02 11:53 +0000
                Re: revisiting a prgramming problem the_gavino_himself <visphatesjava@gmail.com> - 2014-12-02 05:23 -0800
                Re: revisiting a prgramming problem rickman <gnuarm@gmail.com> - 2014-12-02 09:01 -0500
        Re: revisiting a prgramming problem Hans Bezemer <the.beez.speaks@gmail.com> - 2014-10-21 22:25 +0200
          Re: revisiting a prgramming problem Paul Rubin <no.email@nospam.invalid> - 2014-10-21 16:10 -0700
            Re: revisiting a prgramming problem the_gavino_himself <visphatesjava@gmail.com> - 2014-11-08 21:41 -0800
        Re: revisiting a prgramming problem Hans Bezemer <the.beez.speaks@gmail.com> - 2014-10-21 22:30 +0200
          Re: revisiting a prgramming problem the_gavino_himself <visphatesjava@gmail.com> - 2014-12-01 22:45 -0800
        Re: revisiting a prgramming problem Hans Bezemer <the.beez.speaks@gmail.com> - 2014-10-21 23:04 +0200
      Re: revisiting a prgramming problem Mark Wills <markwills1970@gmail.com> - 2014-10-21 10:17 -0700
        Re: revisiting a prgramming problem "Rod Pemberton" <buzzoff@nonamewhichexists.cmm> - 2014-10-22 02:13 -0400
          Re: revisiting a prgramming problem Paul Rubin <no.email@nospam.invalid> - 2014-10-21 23:26 -0700
            Re: revisiting a prgramming problem "Alex McDonald" <blog@rivadpm.com> - 2014-10-22 16:18 +0100
              Re: revisiting a prgramming problem mhx@iae.nl (Marcel Hendrix) - 2014-10-22 21:27 +0200
                Re: revisiting a prgramming problem albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-10-24 10:30 +0000
                Optimal comparisons for m maximums from n items  (was Re: revisiting a prgramming problem) "Alex McDonald" <blog@rivadpm.com> - 2014-10-24 16:29 +0100
                Re: Optimal comparisons for m maximums from n items  (was Re: revisiting a prgramming problem) albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-10-25 08:27 +0000
                Re: Optimal comparisons for m maximums from n items (was Re: revisiting a prgramming problem) "Alex McDonald" <blog@rivadpm.com> - 2014-10-25 18:54 +0100
                Re: revisiting a prgramming problem mhx@iae.nl (Marcel Hendrix) - 2014-10-25 13:28 +0200
                Re: revisiting a prgramming problem mhx@iae.nl (Marcel Hendrix) - 2014-10-25 14:28 +0200
                Re: revisiting a prgramming problem mhx@iae.nl (Marcel Hendrix) - 2014-10-25 15:17 +0200
            Re: revisiting a prgramming problem Gerry Jackson <spam@qlikz.org> - 2014-10-22 21:57 +0100
              Re: revisiting a prgramming problem Paul Rubin <no.email@nospam.invalid> - 2014-10-22 14:06 -0700
                Re: revisiting a prgramming problem Bernd Paysan <bernd.paysan@gmx.de> - 2014-10-23 00:03 +0200
                Re: revisiting a prgramming problem albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-10-23 14:46 +0000
                Re: revisiting a prgramming problem Paul Rubin <no.email@nospam.invalid> - 2014-10-23 08:16 -0700
                Re: revisiting a prgramming problem "Alex McDonald" <blog@rivadpm.com> - 2014-10-23 19:21 +0100
                Re: revisiting a prgramming problem "Alex McDonald" <blog@rivadpm.com> - 2014-10-23 20:02 +0100
                Re: revisiting a prgramming problem albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-10-23 20:29 +0000
                Re: revisiting a prgramming problem Coos Haak <chforth@hccnet.nl> - 2014-10-23 22:23 +0200
              Re: revisiting a prgramming problem awegel@arcor.de (Alexander Wegel) - 2014-10-23 00:36 +0200
                Re: revisiting a prgramming problem Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2014-10-24 10:44 +0100
              Re: revisiting a prgramming problem hughaguilar96@yahoo.com - 2014-10-22 17:26 -0700
                Re: revisiting a prgramming problem Michael Barry <barrym95838@yahoo.com> - 2014-10-23 00:02 -0700
          Re: revisiting a prgramming problem the_gavino_himself <visphatesjava@gmail.com> - 2014-11-08 23:10 -0800
        Re: revisiting a prgramming problem the_gavino_himself <visphatesjava@gmail.com> - 2014-11-08 21:42 -0800
  Re: revisiting a prgramming problem Roger Levy <roger.levy@gmail.com> - 2014-10-15 08:18 -0700
    Re: revisiting a prgramming problem Roger Levy <roger.levy@gmail.com> - 2014-10-15 08:18 -0700
      Re: revisiting a prgramming problem november.nihal@gmail.com - 2014-10-15 08:57 -0700
      Re: revisiting a prgramming problem Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2014-10-15 17:10 +0100
      Re: revisiting a prgramming problem "Rod Pemberton" <buzzoff@nonamewhichexists.cmm> - 2014-10-17 21:53 -0400
    Re: revisiting a prgramming problem Roger Levy <roger.levy@gmail.com> - 2014-10-15 08:19 -0700
  Re: revisiting a prgramming problem awegel@arcor.de (Alexander Wegel) - 2014-10-22 00:30 +0200
    Re: revisiting a prgramming problem hughaguilar96@yahoo.com - 2014-10-21 16:07 -0700
      Re: revisiting a prgramming problem awegel@arcor.de (Alexander Wegel) - 2014-10-22 03:23 +0200
        Re: revisiting a prgramming problem "Rod Pemberton" <buzzoff@nonamewhichexists.cmm> - 2014-10-22 02:15 -0400
          Re: revisiting a prgramming problem awegel@arcor.de (Alexander Wegel) - 2014-10-22 12:52 +0200
        Re: revisiting a prgramming problem hughaguilar96@yahoo.com - 2014-10-22 17:19 -0700
          Re: revisiting a prgramming problem awegel@arcor.de (Alexander Wegel) - 2014-10-23 16:10 +0200
      Re: revisiting a prgramming problem "Rod Pemberton" <buzzoff@nonamewhichexists.cmm> - 2014-10-22 02:14 -0400
      Re: revisiting a prgramming problem the_gavino_himself <visphatesjava@gmail.com> - 2014-11-08 23:21 -0800
      Re: revisiting a prgramming problem "WJ" <w_a_x_man@yahoo.com> - 2014-12-06 02:34 +0000
      Re: revisiting a prgramming problem "WJ" <w_a_x_man@yahoo.com> - 2014-12-27 08:00 +0000
        Re: revisiting a prgramming problem Mark Wills <markwills1970@gmail.com> - 2014-12-27 05:15 -0800
  Re: revisiting a prgramming problem "WJ" <w_a_x_man@yahoo.com> - 2014-11-29 17:20 +0000
    Re: revisiting a prgramming problem the_gavino_himself <visphatesjava@gmail.com> - 2014-11-29 12:00 -0800
    Re: revisiting a prgramming problem "WJ" <w_a_x_man@yahoo.com> - 2014-12-02 16:15 +0000
  Re: revisiting a prgramming problem Paul Sephton <prsephton@gmail.com> - 2014-12-02 05:06 -0800
    Re: revisiting a prgramming problem Paul Sephton <prsephton@gmail.com> - 2014-12-02 05:14 -0800
    Re: revisiting a prgramming problem the_gavino_himself <visphatesjava@gmail.com> - 2014-12-02 05:24 -0800

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