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Groups > comp.lang.forth > #16549

Re: FORTH Trouble--Please Show Me

From Paul Rubin <no.email@nospam.invalid>
Newsgroups comp.lang.forth
Subject Re: FORTH Trouble--Please Show Me
References <7x3917hacl.fsf@ruckus.brouhaha.com> <87851214938435@frunobulax.edu>
Date 2012-10-21 17:11 -0700
Message-ID <7xzk3fmkm2.fsf@ruckus.brouhaha.com> (permalink)
Organization Nightsong/Fort GNOX

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mhx@iae.nl (Marcel Hendrix) writes:
> ANEW -derivative
>
> : eval ( ? xt -- ? ) ( F: ? -- ? ) EXECUTE ;
>
> : derivative ( xt -- ) ( F: x h -- d )
>   LOCAL f   FLOCALS| h x |
>   x h F+ f eval   x f eval  F-  h F/ ;
>
> CR 3e FSQR  F.                  \ prints 9
> CR ' FSQR 3e 1e-4 derivative F. \ prints approximately 6

If I understand this, it doesn't actually create a closure.  Rather, it
passes a function as an arg to derivative that gets called during the
call to derivative, so if you want to compute two derivatives you have
to call "derivative" twice.  Maybe I'm wrong.  Can you do this slightly
modified example?  Change

    print square(3)  # prints 9
    print derivative(square,0.0001)(3)   # prints approximately 6

to:

    print square(3)  # prints 9
    d = derivative(square, 0.00001)
    print d(3)    # prints approximately 6
    print d(4)    # prints approximately 8

I may not have made it clear enough earlier: the thing coming back from
"derivative" is a value that you can (for example) save in the variable
"d" (like above).  That value is the closure.

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Thread

FORTH Trouble--Please Show Me "Charles Richmond" <numerist@aquaporin4.com> - 2012-10-17 16:56 -0500
  Re: FORTH Trouble--Please Show Me all2001@spambog.com (Wolfgang Allinger) - 2012-10-17 19:11 -0300
    Re: FORTH Trouble--Please Show Me Mark Wills <forthfreak@gmail.com> - 2012-10-18 01:15 -0700
      Re: FORTH Trouble--Please Show Me "Charles Richmond" <numerist@aquaporin4.com> - 2012-10-18 05:25 -0500
  Re: FORTH Trouble--Please Show Me mhx@iae.nl (Marcel Hendrix) - 2012-10-18 00:14 +0200
    Re: FORTH Trouble--Please Show Me Spam@ControlQ.com - 2012-10-17 18:45 -0400
      Re: FORTH Trouble--Please Show Me Anonymous <nobody@remailer.paranoici.org> - 2012-10-18 08:49 +0000
        Re: FORTH Trouble--Please Show Me Spam@ControlQ.com - 2012-10-18 15:58 -0400
          Re: FORTH Trouble--Please Show Me albert@spenarnc.xs4all.nl (Albert van der Horst) - 2012-10-18 21:53 +0000
          Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-19 18:39 -0700
            Re: FORTH Trouble--Please Show Me Mark Wills <markrobertwills@yahoo.co.uk> - 2012-10-19 23:22 -0700
            Re: FORTH Trouble--Please Show Me "Charles Richmond" <numerist@aquaporin4.com> - 2012-10-21 13:40 -0500
          Re: FORTH Trouble--Please Show Me "Elizabeth D. Rather" <erather@forth.com> - 2012-10-19 21:00 -1000
            Re: FORTH Trouble--Please Show Me "A. K." <akk@nospam.org> - 2012-10-20 09:18 +0200
              Re: FORTH Trouble--Please Show Me "Elizabeth D. Rather" <erather@forth.com> - 2012-10-20 08:40 -1000
          Re: FORTH Trouble--Please Show Me mhx@iae.nl (Marcel Hendrix) - 2012-10-21 12:22 +0200
            Re: FORTH Trouble--Please Show Me Doug Hoffman <glidedog@gmail.com> - 2012-10-21 08:46 -0400
      Re: FORTH Trouble--Please Show Me mhx@iae.nl (Marcel Hendrix) - 2012-10-18 21:08 +0200
        Re: FORTH Trouble--Please Show Me Mark Wills <markrobertwills@yahoo.co.uk> - 2012-10-18 12:29 -0700
  Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-17 20:24 -0700
    Re: FORTH Trouble--Please Show Me "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-10-19 19:46 -0400
      Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-19 18:46 -0700
        Re: FORTH Trouble--Please Show Me "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-10-20 21:03 -0400
          Re: FORTH Trouble--Please Show Me "Elizabeth D. Rather" <erather@forth.com> - 2012-10-20 15:40 -1000
          Re: FORTH Trouble--Please Show Me Paul Rubin <no.email@nospam.invalid> - 2012-10-20 18:52 -0700
            Re: FORTH Trouble--Please Show Me "Elizabeth D. Rather" <erather@forth.com> - 2012-10-20 16:27 -1000
          Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-20 20:56 -0700
            Re: FORTH Trouble--Please Show Me "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-10-21 09:40 -0400
              Re: FORTH Trouble--Please Show Me Paul Rubin <no.email@nospam.invalid> - 2012-10-21 12:51 -0700
                Re: FORTH Trouble--Please Show Me mhx@iae.nl (Marcel Hendrix) - 2012-10-21 23:50 +0200
                Re: FORTH Trouble--Please Show Me Paul Rubin <no.email@nospam.invalid> - 2012-10-21 17:11 -0700
                Re: FORTH Trouble--Please Show Me mhx@iae.nl - 2012-10-22 00:19 -0700
                Re: FORTH Trouble--Please Show Me Paul Rubin <no.email@nospam.invalid> - 2012-10-22 00:41 -0700
                Re: FORTH Trouble--Please Show Me Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-10-22 09:31 -0500
                Re: FORTH Trouble--Please Show Me Paul Rubin <no.email@nospam.invalid> - 2012-10-22 08:13 -0700
                Re: FORTH Trouble--Please Show Me mhx@iae.nl (Marcel Hendrix) - 2012-10-22 21:40 +0200
                Re: FORTH Trouble--Please Show Me Paul Rubin <no.email@nospam.invalid> - 2012-10-22 13:14 -0700
                Re: FORTH Trouble--Please Show Me "Elizabeth D. Rather" <erather@forth.com> - 2012-10-22 10:41 -1000
                Re: FORTH Trouble--Please Show Me mhx@iae.nl (Marcel Hendrix) - 2012-10-22 23:21 +0200
                Re: FORTH Trouble--Please Show Me Paul Rubin <no.email@nospam.invalid> - 2012-10-22 14:27 -0700
                Re: FORTH Trouble--Please Show Me "Elizabeth D. Rather" <erather@forth.com> - 2012-10-22 14:16 -1000
                Re: FORTH Trouble--Please Show Me Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2012-10-23 21:42 +0100
                Re: FORTH Trouble--Please Show Me vandys@vsta.org - 2012-10-22 00:24 +0000
                Re: FORTH Trouble--Please Show Me "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-10-22 04:12 -0400
                Re: FORTH Trouble--Please Show Me Paul Rubin <no.email@nospam.invalid> - 2012-10-22 01:40 -0700
                Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-22 02:39 -0700
                Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-22 02:30 -0700
                Re: FORTH Trouble--Please Show Me "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-10-22 22:27 -0400
                Re: FORTH Trouble--Please Show Me David Thompson <dave.thompson2@verizon.net> - 2012-11-04 22:18 -0500
                Re: FORTH Trouble--Please Show Me Bernd Paysan <bernd.paysan@gmx.de> - 2012-11-05 15:35 +0100
                Re: FORTH Trouble--Please Show Me humptydumpty <ouatubi@gmail.com> - 2012-10-22 12:22 -0700
                Re: FORTH Trouble--Please Show Me Paul Rubin <no.email@nospam.invalid> - 2012-10-22 12:51 -0700
                Re: FORTH Trouble--Please Show Me humptydumpty <ouatubi@gmail.com> - 2012-10-22 23:40 -0700
                Re: FORTH Trouble--Please Show Me anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-10-23 12:50 +0000
                Re: FORTH Trouble--Please Show Me humptydumpty <ouatubi@gmail.com> - 2012-10-24 09:13 -0700
                Re: FORTH Trouble--Please Show Me anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-10-25 12:31 +0000
                Re: FORTH Trouble--Please Show Me humptydumpty <ouatubi@gmail.com> - 2012-10-26 09:58 -0700
              Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-21 16:24 -0700
                Re: FORTH Trouble--Please Show Me Bernd Paysan <bernd.paysan@gmx.de> - 2012-10-22 02:51 +0200
                Re: FORTH Trouble--Please Show Me Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-10-21 19:55 -0500
                Re: FORTH Trouble--Please Show Me Bernd Paysan <bernd.paysan@gmx.de> - 2012-10-22 03:02 +0200
                Re: FORTH Trouble--Please Show Me "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-10-22 03:50 -0400
                Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-22 01:03 -0700
                Re: FORTH Trouble--Please Show Me stephenXXX@mpeforth.com (Stephen Pelc) - 2012-10-22 10:12 +0000
                Re: FORTH Trouble--Please Show Me stephenXXX@mpeforth.com (Stephen Pelc) - 2012-10-22 10:08 +0000
                Re: FORTH Trouble--Please Show Me Bernd Paysan <bernd.paysan@gmx.de> - 2012-10-22 18:06 +0200
                Re: FORTH Trouble--Please Show Me mhx@iae.nl (Marcel Hendrix) - 2012-10-22 22:14 +0200
                Re: FORTH Trouble--Please Show Me albert@spenarnc.xs4all.nl (Albert van der Horst) - 2012-10-23 00:50 +0000
                Re: FORTH Trouble--Please Show Me Bernd Paysan <bernd.paysan@gmx.de> - 2012-10-23 03:43 +0200
                Re: FORTH Trouble--Please Show Me Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-10-23 03:14 -0500
                Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-22 19:54 -0700
                Re: FORTH Trouble--Please Show Me Mark Wills <markrobertwills@yahoo.co.uk> - 2012-10-22 22:59 -0700
                Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-24 09:23 -0700
                Re: FORTH Trouble--Please Show Me stephenXXX@mpeforth.com (Stephen Pelc) - 2012-10-23 10:33 +0000
                Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-24 10:05 -0700
                Re: FORTH Trouble--Please Show Me Doug Hoffman <glidedog@gmail.com> - 2012-10-24 14:56 -0400
                Re: FORTH Trouble--Please Show Me anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-10-23 11:50 +0000
                Re: FORTH Trouble--Please Show Me stephenXXX@mpeforth.com (Stephen Pelc) - 2012-10-23 14:39 +0000
                Application Benchmarks (was: FORTH Trouble--Please Show Me) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-10-23 15:59 +0000
                Re: Application Benchmarks (was: FORTH Trouble--Please Show Me) stephenXXX@mpeforth.com (Stephen Pelc) - 2012-10-24 14:33 +0000
                Re: Application Benchmarks (was: FORTH Trouble--Please Show Me) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-10-25 14:19 +0000
                Re: FORTH Trouble--Please Show Me "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-10-22 03:56 -0400
                Re: FORTH Trouble--Please Show Me "Elizabeth D. Rather" <erather@forth.com> - 2012-10-21 22:12 -1000
                Re: FORTH Trouble--Please Show Me Hugh Aguilar <hughaguilar96@yahoo.com> - 2012-10-22 02:51 -0700
          Re: FORTH Trouble--Please Show Me Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-10-21 05:29 -0500
            Re: FORTH Trouble--Please Show Me "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-10-21 09:35 -0400
            Re: FORTH Trouble--Please Show Me Bernd Paysan <bernd.paysan@gmx.de> - 2012-10-21 15:44 +0200
              Re: FORTH Trouble--Please Show Me Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-10-21 18:43 -0500
              Re: FORTH Trouble--Please Show Me "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2012-10-22 04:20 -0400

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