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Re: Programming D. E. Knuth in Python with the Deterministic Finite Automaton construct

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On 3/17/2012 15:03, Antti J Ylikoski wrote:
> In his legendary book series The Art of Computer Programming,
> Professor Donald E. Knuth presents many of his algorithms in the form
> that they have been divided in several individual phases, with
> instructions to GOTO to another phase interspersed in the text of the
> individual phases.
>
>
>
> I. e. they look like the following, purely invented, example: (Knuth is
> being clearer than me below.....)
>
>
>
> A1. (Do the work of Phase A1.) If <zap> then go to Phase A5,
> otherwise continue.
>
> A2. (Do some work.) If <zorp> go to Phase A4.
>
> A3. (Some more work.)
>
> A4. (Do something.) If <condition ZZZ> go to Phase A1.
>
> A5. (Something more). If <foobar> then go to Phase A2, otherwise
> end.
>
>
>
> I came across the problem, which would be the clearest way to program
> such algorithms with a programming language such as Python, which has
> no GOTO statement. It struck me that the above construction actually
> is a modified Deterministic Finite Automaton with states A1 -- A5 +
> [END], transferring to different states, not on read input, but
> according to conditions in the running program.

A1 and A5 are NOT states: they're labels.
There is no garanteed bijection from labels to states.

> So one very clear way to program Knuth with Python is the following
> kind of a construct.
[...]

Your way is easy, but the result is poor.
Your should try to rewrite it. Decompilers do exactly that.

Kiuhnm

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Programming D. E. Knuth in Python with the Deterministic Finite Automaton construct Antti J Ylikoski <antti.ylikoski@tkk.fi> - 2012-03-17 16:03 +0200
  Re: Programming D. E. Knuth in Python with the Deterministic Finite Automaton construct Mel Wilson <mwilson@the-wire.com> - 2012-03-17 10:39 -0400
  Re: Programming D. E. Knuth in Python with the Deterministic Finite Automaton construct Kiuhnm <kiuhnm03.4t.yahoo.it> - 2012-03-17 15:45 +0100
    Re: Programming D. E. Knuth in Python with the Deterministic Finite Automaton construct Michael Torrie <torriem@gmail.com> - 2012-03-17 09:01 -0600
      Re: Programming D. E. Knuth in Python with the Deterministic Finite Automaton construct Kiuhnm <kiuhnm03.4t.yahoo.it> - 2012-03-17 16:12 +0100
        Re: Programming D. E. Knuth in Python with the Deterministic Finite Automaton construct Michael Torrie <torriem@gmail.com> - 2012-03-17 09:53 -0600
          Re: Programming D. E. Knuth in Python with the Deterministic Finite Automaton construct Kiuhnm <kiuhnm03.4t.yahoo.it> - 2012-03-17 18:55 +0100
            Re: Programming D. E. Knuth in Python with the Deterministic Finite Automaton construct Michael Torrie <torriem@gmail.com> - 2012-03-17 17:28 -0600
              Re: Programming D. E. Knuth in Python with the Deterministic Finite Automaton construct Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-03-18 01:54 +0000
                Re: Programming D. E. Knuth in Python with the Deterministic Finite Automaton construct Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-03-18 11:03 +0000
              Re: Programming D. E. Knuth in Python with the Deterministic Finite Automaton construct Kiuhnm <kiuhnm03.4t.yahoo.it> - 2012-03-19 02:02 +0100
                Re: Programming D. E. Knuth in Python with the Deterministic Finite Automaton construct Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-03-19 01:02 -0400
                Re: Programming D. E. Knuth in Python with the Deterministic Finite Automaton construct Kiuhnm <kiuhnm03.4t.yahoo.it> - 2012-03-19 11:24 +0100
  Re: Programming D. E. Knuth in Python with the Deterministic Finite Automaton construct Roy Smith <roy@panix.com> - 2012-03-17 11:47 -0400
    Re: Programming D. E. Knuth in Python with the Deterministic Finite Automaton construct Antti J Ylikoski <antti.ylikoski@tkk.fi> - 2012-03-17 18:31 +0200
      Re: Programming D. E. Knuth in Python with the Deterministic Finite Automaton construct John Nagle <nagle@animats.com> - 2012-03-17 11:44 -0700
  Re: Programming D. E. Knuth in Python with the Deterministic Finite Automaton construct Evan Driscoll <driscoll@cs.wisc.edu> - 2012-03-17 21:59 -0500
  Re: Programming D. E. Knuth in Python with the Deterministic Finite Automaton construct Albert van der Horst <albert@spenarnc.xs4all.nl> - 2012-03-18 11:08 +0000

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