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Re: Genral advise and comments on callback style words

From anton@mips.complang.tuwien.ac.at (Anton Ertl)
Newsgroups comp.lang.forth
Subject Re: Genral advise and comments on callback style words
Date 2012-11-08 16:31 +0000
Organization Institut fuer Computersprachen, Technische Universitaet Wien
Message-ID <2012Nov8.173134@mips.complang.tuwien.ac.at> (permalink)
References <2012110713421835115-chrishinsley@gmailcom> <2012Nov7.145519@mips.complang.tuwien.ac.at> <2012110715375130718-chrishinsley@gmailcom>

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Chris Hinsley <chris.hinsley@gmail.com> writes:
>> However, the may thing I want to point out is that in my experience
>> it's a good idea if the wrapper word (LISTHEAD-ENUMERATE-FORWARDS in
>> this case) does not keep its data on the data stack during the
>> callback, and thus allows the caller to pass additional data to the
>> called-back word
>
>The u paramater here is exactly that ! A user data value, pointer to 
>structure or whatever. It can be used to pass information to the 
>callback or be used by the callback to pass data onto the next callback 
>invocation etc. It's very flexable.

It's even more flexible if you avoid any internal data on the data
stack during the callback, because that allows passing an arbitrary
number of stack elements into and out of the callback, not just one.

- anton
-- 
M. Anton Ertl  http://www.complang.tuwien.ac.at/anton/home.html
comp.lang.forth FAQs: http://www.complang.tuwien.ac.at/forth/faq/toc.html
     New standard: http://www.forth200x.org/forth200x.html
   EuroForth 2012: http://www.euroforth.org/ef12/

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Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-07 13:42 +0000
  Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-07 13:51 +0000
    Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-07 13:56 +0000
  Re: Genral advise and comments on callback style words anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-11-07 13:55 +0000
    Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-07 15:29 +0000
      Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-07 15:35 +0000
    Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-07 15:32 +0000
    Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-07 15:37 +0000
      Re: Genral advise and comments on callback style words anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-11-08 16:31 +0000
        Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 17:02 +0000
          Re: Genral advise and comments on callback style words anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-11-08 17:07 +0000
          Re: Genral advise and comments on callback style words Mark Wills <forthfreak@gmail.com> - 2012-11-09 01:16 -0800
    Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-07 15:41 +0000
      Re: Genral advise and comments on callback style words anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-11-08 16:39 +0000
  Re: Genral advise and comments on callback style words Brad Eckert <hwfwguy@gmail.com> - 2012-11-07 08:07 -0800
    Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 12:52 +0000
  Re: Genral advise and comments on callback style words humptydumpty <ouatubi@gmail.com> - 2012-11-07 13:04 -0800
    Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 13:04 +0000
      Re: Genral advise and comments on callback style words Mark Wills <forthfreak@gmail.com> - 2012-11-08 06:34 -0800
        Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 14:40 +0000
    Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 13:14 +0000
      Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 13:23 +0000
      Re: Genral advise and comments on callback style words Ouatu Bogdan <ouatubi@gmail.com> - 2012-11-08 13:45 +0000
        Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 13:59 +0000
        Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 14:02 +0000
          Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 15:35 +0000
            Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 16:24 +0000
              Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 16:39 +0000
                Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 16:57 +0000
                Re: Genral advise and comments on callback style words "Elizabeth D. Rather" <erather@forth.com> - 2012-11-08 07:56 -1000
  Re: Genral advise and comments on callback style words Josh Grams <josh@qualdan.com> - 2012-11-08 13:54 +0000
    Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 14:06 +0000
      Re: Genral advise and comments on callback style words Josh Grams <josh@qualdan.com> - 2012-11-08 18:04 +0000
        Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 19:36 +0000
        Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 19:38 +0000
          Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 19:42 +0000
    Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 14:11 +0000
      Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 14:31 +0000
        Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 14:51 +0000
          Re: Genral advise and comments on callback style words Josh Grams <josh@qualdan.com> - 2012-11-08 18:23 +0000
            Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 19:57 +0000
            Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 20:04 +0000
              Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 20:17 +0000
                Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 20:29 +0000
                Re: Genral advise and comments on callback style words Chris Hinsley <chris.hinsley@gmail.com> - 2012-11-08 20:50 +0000

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