Re: RFD Recognizer

From	Bernd Paysan <bernd.paysan@gmx.de>
Newsgroups	comp.lang.forth
Subject	Re: RFD Recognizer
Date	2015-01-03 16:08 +0100
Organization	A noiseless patient Spider
Message-ID	<m890kr$5ud$1@dont-email.me> (permalink)
References	<de1bad94-b5e9-468b-9673-9fcb963c1622@googlegroups.com> <QrednZcoJNYbSTrJnZ2dnUU7-Q2dnZ2d@supernews.com>

Show all headers | View raw

Andrew Haley wrote:
> 2.  This proposal looks rather complicated.  Can it not be made simpler
>     without loss of functionality?  For example, R:FAIL does not seem
>     to do anything useful.  It's very cute to make it the failure
>     action but there's an awful lot of DUP R:FAIL <> IF executed in
>     the inner loop of DO-RECOGNIZER.  Should the token used for
>     notifying a failure not simply be zero?

If I look at my implementation, there is one DUP R:FAIL <> IF check in the 
inner loop of DO-RECOGNIZER.  There are three users of DO-RECOGNIZER, the 
interpreter, the compiler, and the postpone loop.  Having a 0 would simplify 
the one check in the inner loop to DUP IF and complicate the three users of 
DO-RECOGNIZER, which then all need special-casing the fail case.

The reference implementation takes the same approach.

I'm fairly convinced that the tradeoff is better the way it is now.  You 
actully can implement R:FAIL as 0 if you like, as it is an opaque type; all 
consumers of recognizers are interal stuff in INTERPRET and POSTPONE, and 
you are, as implementer, free to choose the tradeoffs as you like.

The recognizer stack works like the search order stack, the SET-RECOGNIZERS 
and GET-RECOGNIZERS give you access to the stack in the same way as SET-
ORDER and GET-ORDER does.

The proposal asks one question at the end, how to POSTPONE literals, and the 
obvious answer is that you just append the compilation semantics of those 
literals to the current definition when you execute that postponed literal.

The question whether you allow to put some other recognizer in front of the 
dictionary lookup is up to the user - I would rather not put constraints 
here.  This approach is not limited to literals.

-- 
Bernd Paysan
"If you want it done right, you have to do it yourself"
http://bernd-paysan.de/

Thread

RFD Recognizer Matthias Trute <matthias.trute@gmail.com> - 2015-01-02 11:56 -0800
  Re: RFD Recognizer Andrew Haley <andrew29@littlepinkcloud.invalid> - 2015-01-03 05:37 -0600
    Re: RFD Recognizer anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-01-03 12:56 +0000
      Re: RFD Recognizer Andrew Haley <andrew29@littlepinkcloud.invalid> - 2015-01-04 04:23 -0600
        Re: RFD Recognizer anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-01-04 11:25 +0000
          Re: RFD Recognizer Andrew Haley <andrew29@littlepinkcloud.invalid> - 2015-01-05 04:43 -0600
            Re: RFD Recognizer anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-01-05 12:35 +0000
              Re: RFD Recognizer Andrew Haley <andrew29@littlepinkcloud.invalid> - 2015-01-06 10:33 -0600
                Re: RFD Recognizer anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-01-07 15:29 +0000
                Re: RFD Recognizer Andrew Haley <andrew29@littlepinkcloud.invalid> - 2015-01-07 12:57 -0600
                Re: RFD Recognizer Matthias Trute <matthias.trute@gmail.com> - 2015-01-07 12:27 -0800
                Re: RFD Recognizer Bernd Paysan <bernd.paysan@gmx.de> - 2015-01-09 00:42 +0100
                Re: RFD Recognizer albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-01-07 20:55 +0000
    Re: RFD Recognizer Matthias Trute <matthias.trute@gmail.com> - 2015-01-03 06:43 -0800
      Re: RFD Recognizer JennyB <jennybrien@googlemail.com> - 2015-01-03 07:54 -0800
        Re: RFD Recognizer Matthias Trute <matthias.trute@gmail.com> - 2015-01-03 08:37 -0800
          Re: RFD Recognizer JennyB <jennybrien@googlemail.com> - 2015-01-03 10:08 -0800
        Re: RFD Recognizer anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-01-04 12:15 +0000
          Re: RFD Recognizer JennyB <jennybrien@googlemail.com> - 2015-01-09 10:15 -0800
            Re: RFD Recognizer Matthias Trute <matthias.trute@gmail.com> - 2015-01-09 12:11 -0800
              Re: RFD Recognizer Bernd Paysan <bernd.paysan@gmx.de> - 2015-01-09 22:46 +0100
      Re: RFD Recognizer Andrew Haley <andrew29@littlepinkcloud.invalid> - 2015-01-04 04:37 -0600
        Re: RFD Recognizer Matthias Trute <matthias.trute@gmail.com> - 2015-01-04 06:32 -0800
          Re: RFD Recognizer Andrew Haley <andrew29@littlepinkcloud.invalid> - 2015-01-05 04:55 -0600
            Re: RFD Recognizer Matthias Trute <matthias.trute@gmail.com> - 2015-01-05 10:06 -0800
      Re: RFD Recognizer albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-01-04 16:02 +0000
        Re: RFD Recognizer Matthias Trute <matthias.trute@gmail.com> - 2015-01-04 11:06 -0800
          Re: RFD Recognizer JennyB <jennybrien@googlemail.com> - 2015-01-05 08:18 -0800
            Re: RFD Recognizer JennyB <jennybrien@googlemail.com> - 2015-01-05 08:59 -0800
            Re: RFD Recognizer Matthias Trute <matthias.trute@gmail.com> - 2015-01-05 10:23 -0800
              Re: RFD Recognizer anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-01-08 15:36 +0000
                Re: RFD Recognizer Matthias Trute <matthias.trute@gmail.com> - 2015-01-08 10:54 -0800
                Re: RFD Recognizer Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2015-01-08 20:50 +0000
          Re: RFD Recognizer anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-01-08 14:24 +0000
            Re: RFD Recognizer albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-01-08 16:06 +0000
            Re: RFD Recognizer Bernd Paysan <bernd.paysan@gmx.de> - 2015-01-09 01:11 +0100
        Re: RFD Recognizer Matthias Koch <matthias.koch@hot.uni-hannover.de> - 2015-01-05 17:19 +0100
    Re: RFD Recognizer Bernd Paysan <bernd.paysan@gmx.de> - 2015-01-03 16:08 +0100
    Re: RFD Recognizer hughaguilar96@gmail.com - 2015-01-03 16:05 -0800
      Re: RFD Recognizer Andrew Haley <andrew29@littlepinkcloud.invalid> - 2015-01-04 04:42 -0600
      Re: RFD Recognizer stephen@mpeforth.com (Stephen Pelc) - 2015-01-06 18:01 +0000
    Re: RFD Recognizer albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-01-04 15:11 +0000
      Re: RFD Recognizer Andrew Haley <andrew29@littlepinkcloud.invalid> - 2015-01-05 05:00 -0600
        Re: RFD Recognizer albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-01-05 13:39 +0000
          Re: RFD Recognizer Andrew Haley <andrew29@littlepinkcloud.invalid> - 2015-01-06 04:57 -0600
            Re: RFD Recognizer albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-01-06 18:00 +0000
              Re: RFD Recognizer Andrew Haley <andrew29@littlepinkcloud.invalid> - 2015-01-07 05:13 -0600
                Re: RFD Recognizer albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-01-07 17:18 +0000
                Re: RFD Recognizer Andrew Haley <andrew29@littlepinkcloud.invalid> - 2015-01-07 13:04 -0600
  Re: RFD Recognizer Julian Fondren <julian.fondren@gmail.com> - 2015-01-04 07:48 -0800
    Re: RFD Recognizer JennyB <jennybrien@googlemail.com> - 2015-01-05 06:01 -0800
      Re: RFD Recognizer anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-01-05 14:31 +0000
        Re: RFD Recognizer JennyB <jennybrien@googlemail.com> - 2015-01-05 08:43 -0800
          Re: RFD Recognizer anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-01-08 15:22 +0000
        Re: RFD Recognizer Bernd Paysan <bernd.paysan@gmx.de> - 2015-01-06 02:48 +0100
          Re: RFD Recognizer albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-01-06 03:13 +0000
    Re: RFD Recognizer anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-01-08 13:45 +0000
  Re: RFD Recognizer Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2015-01-08 20:44 +0000
    Re: RFD Recognizer JennyB <jennybrien@googlemail.com> - 2015-01-17 09:26 -0800
      Re: RFD Recognizer Bernd Paysan <bernd.paysan@gmx.de> - 2015-01-17 18:54 +0100
        Re: RFD Recognizer JennyB <jennybrien@googlemail.com> - 2015-01-17 12:35 -0800
      Re: RFD Recognizer Matthias Trute <matthias.trute@gmail.com> - 2015-01-18 04:16 -0800
        Re: RFD Recognizer albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-01-18 13:38 +0000
          Re: RFD Recognizer anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-01-18 13:56 +0000
            Re: RFD Recognizer JennyB <jennybrien@googlemail.com> - 2015-01-18 07:10 -0800
              Re: RFD Recognizer anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-01-18 16:14 +0000
      Re: RFD Recognizer Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2015-01-20 18:26 +0000
        Re: RFD Recognizer Bernd Paysan <bernd.paysan@gmx.de> - 2015-01-20 23:54 +0100
          Re: RFD Recognizer JennyB <jennybrien@googlemail.com> - 2015-01-21 09:05 -0800
            Re: RFD Recognizer Bernd Paysan <bernd.paysan@gmx.de> - 2015-01-21 20:50 +0100
            Re: RFD Recognizer albert@spenarnc.xs4all.nl (Albert van der Horst) - 2015-01-22 10:55 +0000

csiph-web