Re: How detect cycle in grammar ?

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From	Hans Aberg <haberg-news@telia.com>
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Subject	Re: How detect cycle in grammar ?
Date	Mon, 21 Nov 2011 18:14:05 +0100
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On 2011/11/20 17:48, Borneq wrote:
> A->B
> B->B
> This grammar is not correct, B is looped.
>
> A->B
> B->C
> C->A
> This another grammar, cycle can be arbitrarily long.
> Is cycle when First(Nonterminal) not contain any terminal, even not
> epsilon?

If it is only cycles in the graph you are out for, perhaps some
algorithm mentioned here might help:
   https://en.wikipedia.org/wiki/Strongly_connected_component
   https://en.wikipedia.org/wiki/Cycle_detection

Hans

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How detect cycle in grammar ? Borneq <a.moderacja@gmail.com> - 2011-11-20 08:48 -0800
  Re: How detect cycle in grammar ? Hans Aberg <haberg-news@telia.com> - 2011-11-21 18:14 +0100
  Re: How detect cycle in grammar ? Gene <gene.ressler@gmail.com> - 2011-11-21 10:20 -0800
    Re: How detect cycle in grammar ? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2011-11-22 15:20 +0000
      Re: How detect cycle in grammar ? Quinn Tyler Jackson <quinn_jackson2004@yahoo.ca> - 2011-11-25 22:28 -0800
      Re: How detect cycle in grammar ? Gene <gene.ressler@gmail.com> - 2011-11-27 10:18 -0800
    Re: How detect cycle in grammar ? Borneq <a.moderacja@gmail.com> - 2011-11-23 12:56 -0800
    Re: How detect cycle in grammar ? Borneq <a.moderacja@gmail.com> - 2011-11-24 09:24 -0800
      Re: How detect cycle in grammar ? Gene <gene.ressler@gmail.com> - 2011-11-27 10:27 -0800
        Re: How detect cycle in grammar ? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2011-11-28 16:46 +0000
          Re: How detect cycle in grammar ? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2011-11-29 07:31 +0000
            Re: How detect cycle in grammar ? Paul B Mann <paul@paulbmann.com> - 2011-12-01 02:46 -0800
              Re: How detect cycle in grammar ? Quinn Tyler Jackson <quinn_jackson2004@yahoo.ca> - 2011-12-02 09:20 -0800
          Re: How detect cycle in grammar ? Gene <gene.ressler@gmail.com> - 2011-12-07 06:29 -0800

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