Re: 8 queens problem in Oforth

From	Paul Rubin <no.email@nospam.invalid>
Newsgroups	comp.lang.forth
Subject	Re: 8 queens problem in Oforth
Date	2015-03-23 19:08 -0700
Organization	A noiseless patient Spider
Message-ID	<87oanj6tba.fsf@jester.gateway.sonic.net> (permalink)
References	(11 earlier) <menqmi$q1t$1@dont-email.me> <87lhio8iai.fsf@jester.gateway.sonic.net> <2015Mar23.123414@mips.complang.tuwien.ac.at> <87y4mn727h.fsf@jester.gateway.sonic.net> <meq84t$gva$1@dont-email.me>

Show all headers | View raw

Bernd Paysan <bernd.paysan@gmx.de> writes:
> Well, it's a stupid concept.  What you actually want is a parametrized 
> function where you can change the parameter.

That's an implementation technique.  The wanted concept is separate
functions.  Paramatrizing a single function is one way to implement it.
Coding it directly and letting the compiler handle it is another.

> Or an approach where you just reuse that one created function when the
> parameter changes.  That wouldn't be "less convenient".

The Chuck Moore approach to programming is code to solve your immediate
problem, and then rewrite the code if you want to solve a slightly
different problem.  But even Forth has re-usable design patterns, like
the data stack, that aren't always used optimally: sometimes the
convention of words consuming their parameters costs you a few extra
pushes, but we generally follow it to keep the code understandable.
Lisp, Scheme and their descendants have shown HOFs and GC are also
patterns that make the programmer's job easier at the cost of some CPU
cycles.  The benefits make themselves felt more as the programs get more
complicated: Anton's paper on Forth GC starts with one of the better
explanations that I've seen.

In the examples I gave, the HOF approach allowed using the same code for
multiple problems, which would have been required rewriting with the
manual approach.

>> The paper says the program used 17k of memory to compute 6
>> factorial=720.
> Well, seems to be an approach that is entirely counter all the
> traditions of Forth.  Just don't do that.

That was Anton saying he ran those programs on a C64.

> Find a way to do it elegantly, but without the bloat.

GC eliminates the bloat, completely behind the scenes.  Your program
doesn't have to show a trace of concern about it.  You just write your
mathematical thoughts from the clean pure light, and the compiler
carries them out.  What could be more elegant than that?

> : count-wl ( wordlist -- n )  0 [: drop 1+ true ;] rot traverse-wordlist ;
> ... So you have a combination of transient parameters, which exist for
> one call and are gone after that call, and persistent parameters,
> which the function can use but must keep (maybe updated).

OK, that handles a reasonable and useful set of cases.

Thread

8 queens problem in Oforth "WJ" <w_a_x_man@yahoo.com> - 2015-03-19 07:53 +0000
  Re: 8 queens problem in Oforth Paul Rubin <no.email@nospam.invalid> - 2015-03-19 08:58 -0700
    Re: 8 queens problem in Oforth Doug Hoffman <glidedog@gmail.com> - 2015-03-20 08:16 -0400
      Re: 8 queens problem in Oforth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-03-21 10:11 +0000
        Re: 8 queens problem in Oforth franck.bensusan@gmail.com - 2015-03-21 03:45 -0700
          Re: 8 queens problem in Oforth Paul Rubin <no.email@nospam.invalid> - 2015-03-21 14:14 -0700
            Re: 8 queens problem in Oforth franck.bensusan@gmail.com - 2015-03-21 14:28 -0700
              Re: 8 queens problem in Oforth Paul Rubin <no.email@nospam.invalid> - 2015-03-21 14:38 -0700
                Re: 8 queens problem in Oforth franck.bensusan@gmail.com - 2015-03-21 15:15 -0700
                Re: 8 queens problem in Oforth hughaguilar96@gmail.com - 2015-03-21 18:23 -0700
                Re: 8 queens problem in Oforth franck.bensusan@gmail.com - 2015-03-22 03:03 -0700
                Re: 8 queens problem in Oforth hughaguilar96@gmail.com - 2015-03-22 14:04 -0700
                Re: 8 queens problem in Oforth franck.bensusan@gmail.com - 2015-03-22 16:34 -0700
                Re: 8 queens problem in Oforth hughaguilar96@gmail.com - 2015-03-22 21:49 -0700
                Re: 8 queens problem in Oforth Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-03-23 00:05 -0700
                Re: 8 queens problem in Oforth hughaguilar96@gmail.com - 2015-03-23 21:43 -0700
                Re: 8 queens problem in Oforth franck.bensusan@gmail.com - 2015-03-24 04:13 -0700
                Re: 8 queens problem in Oforth franck.bensusan@gmail.com - 2015-03-23 00:17 -0700
                Re: 8 queens problem in Oforth Paul Rubin <no.email@nospam.invalid> - 2015-03-21 19:47 -0700
                Re: 8 queens problem in Oforth franck.bensusan@gmail.com - 2015-03-22 08:41 -0700
                Re: 8 queens problem in Oforth Paul Rubin <no.email@nospam.invalid> - 2015-03-22 13:37 -0700
                Re: 8 queens problem in Oforth Bernd Paysan <bernd.paysan@gmx.de> - 2015-03-22 18:13 +0100
                Re: 8 queens problem in Oforth Paul Rubin <no.email@nospam.invalid> - 2015-03-22 13:55 -0700
                Re: 8 queens problem in Oforth "Alex McDonald" <blog@rivadpm.com> - 2015-03-22 21:08 +0000
                Re: 8 queens problem in Oforth Paul Rubin <no.email@nospam.invalid> - 2015-03-22 14:39 -0700
                Re: 8 queens problem in Oforth Paul Rubin <no.email@nospam.invalid> - 2015-03-22 14:50 -0700
                Re: 8 queens problem in Oforth Bernd Paysan <bernd.paysan@gmx.de> - 2015-03-22 22:58 +0100
                Re: 8 queens problem in Oforth Paul Rubin <no.email@nospam.invalid> - 2015-03-22 15:13 -0700
                Re: 8 queens problem in Oforth Bernd Paysan <bernd.paysan@gmx.de> - 2015-03-23 01:03 +0100
                Re: 8 queens problem in Oforth Paul Rubin <no.email@nospam.invalid> - 2015-03-22 17:33 -0700
                Re: 8 queens problem in Oforth Bernd Paysan <bernd.paysan@gmx.de> - 2015-03-23 02:37 +0100
                Re: 8 queens problem in Oforth hughaguilar96@gmail.com - 2015-03-22 20:53 -0700
                Re: 8 queens problem in Oforth Paul Rubin <no.email@nospam.invalid> - 2015-03-22 21:11 -0700
                Re: 8 queens problem in Oforth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-03-23 11:34 +0000
                Re: 8 queens problem in Oforth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-03-23 19:31 +0000
                Re: 8 queens problem in Oforth Paul Rubin <no.email@nospam.invalid> - 2015-03-23 15:56 -0700
                Re: 8 queens problem in Oforth Bernd Paysan <bernd.paysan@gmx.de> - 2015-03-24 00:38 +0100
                Re: 8 queens problem in Oforth Paul Rubin <no.email@nospam.invalid> - 2015-03-23 19:08 -0700
                Re: 8 queens problem in Oforth hughaguilar96@gmail.com - 2015-03-30 05:02 -0700
                Re: 8 queens problem in Oforth hughaguilar96@gmail.com - 2015-03-30 05:08 -0700
                Re: 8 queens problem in Oforth "Alex McDonald" <blog@rivadpm.com> - 2015-03-30 15:36 +0100
                Re: 8 queens problem in Oforth Bernd Paysan <bernd.paysan@gmx.de> - 2015-03-23 16:46 +0100
                Re: 8 queens problem in Oforth Paul Rubin <no.email@nospam.invalid> - 2015-03-23 15:32 -0700
                Re: 8 queens problem in Oforth Bernd Paysan <bernd.paysan@gmx.de> - 2015-03-23 23:48 +0100
                Re: 8 queens problem in Oforth Paul Rubin <no.email@nospam.invalid> - 2015-03-23 16:14 -0700
                Re: 8 queens problem in Oforth hughaguilar96@gmail.com - 2015-03-22 17:54 -0700
                Re: 8 queens problem in Oforth "Alex McDonald" <blog@rivadpm.com> - 2015-03-22 23:09 +0000
                Re: 8 queens problem in Oforth Bernd Paysan <bernd.paysan@gmx.de> - 2015-03-22 22:11 +0100
                Re: 8 queens problem in Oforth Paul Rubin <no.email@nospam.invalid> - 2015-03-22 14:48 -0700
                Re: 8 queens problem in Oforth hughaguilar96@gmail.com - 2015-03-22 15:11 -0700
                Re: 8 queens problem in Oforth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-03-23 11:29 +0000
                Re: 8 queens problem in Oforth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-03-23 12:20 +0000
                Re: 8 queens problem in Oforth hughaguilar96@gmail.com - 2015-03-22 14:21 -0700
                Re: 8 queens problem in Oforth Coos Haak <chforth@hccnet.nl> - 2015-03-22 22:30 +0100
            Re: 8 queens problem in Oforth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-03-23 14:45 +0000
              Re: 8 queens problem in Oforth Paul Rubin <no.email@nospam.invalid> - 2015-03-23 14:53 -0700
                Re: 8 queens problem in Oforth "Elizabeth D. Rather" <erather@forth.com> - 2015-03-24 09:16 -1000
                Re: 8 queens problem in Oforth Paul Rubin <no.email@nospam.invalid> - 2015-03-24 12:40 -0700
                Re: 8 queens problem in Oforth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-03-30 12:24 +0000
          Re: 8 queens problem in Oforth Coos Haak <chforth@hccnet.nl> - 2015-03-21 22:27 +0100
  Re: 8 queens problem in Oforth "WJ" <w_a_x_man@yahoo.com> - 2015-03-19 20:31 +0000
  Re: 8 queens problem in Oforth "WJ" <w_a_x_man@yahoo.com> - 2015-03-19 20:35 +0000
  Re: 8 queens problem in Oforth "WJ" <w_a_x_man@yahoo.com> - 2015-03-21 17:31 +0000
    Re: 8 queens problem in Oforth "WJ" <w_a_x_man@yahoo.com> - 2015-03-21 20:50 +0000
    Re: 8 queens problem in Oforth "WJ" <w_a_x_man@yahoo.com> - 2015-03-21 21:52 +0000

csiph-web