Re: 8 queens problem in Oforth

From	Bernd Paysan <bernd.paysan@gmx.de>
Newsgroups	comp.lang.forth
Subject	Re: 8 queens problem in Oforth
Date	2015-03-22 22:11 +0100
Organization	A noiseless patient Spider
Message-ID	<menb3k$33e$1@dont-email.me> (permalink)
References	(7 earlier) <87619uav5r.fsf@jester.gateway.sonic.net> <9e9efbe7-b0c8-45a3-9d0a-3dea3651759e@googlegroups.com> <871tkhbvex.fsf@jester.gateway.sonic.net> <memt6i$7lf$1@dont-email.me> <87lhioah1n.fsf@jester.gateway.sonic.net>

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Paul Rubin wrote:

> Bernd Paysan <bernd.paysan@gmx.de> writes:
>> Of course Forth has first-class functions.  We call them "xt", execution
>> tokens.  You can pass them as parameters to other words, you can return
>> an xt as result of a word, you can use xts to define higher order
>> functions.
> 
> Hmm, ok, I hadn't thought of xt's as first-class functions but maybe
> they are.  Is it possible to create them at runtime?  I.e. is there an
> ANS portable way to do something like:
> 
>     \ given functions f and g, make a new function that composes them
>     : compose ( xt1 xt2 -- xt3 ) .... ;
> 
> So this should work:
> 
>    ['] sin ['] sqrt compose constant sin-sqrt      => ok
> 
>    2e sin-sqrt execute f.       => 0.9877659459927356 ok
> 
> That number is sin(sqrt(2)).  "Compose" has made a new xt that combines
> the actions of the previous two.  It's like adding two numbers in order
> to create a new number.  I'd say that to call xt's first class
> functions, you have to be able to do this.

Sure, no doubts about that.  So let's do it:

: compose ( xt1 xt2 -- xt3 ) swap >r >r
  :noname r> compile, r> compile, postpone ; ;

Fixing the bugs in your code, to test it:

' fsin ' fsqrt compose constant sin-sqrt  ok
2e sin-sqrt execute f. 0.987765945992736  ok

Are you happy with that?

-- 
Bernd Paysan
"If you want it done right, you have to do it yourself"
http://bernd-paysan.de/
net2o ID: kQusJzA;7*?t=uy@X}1GWr!+0qqp_Cn176t4(dQ*

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

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