Groups > comp.compilers > #1983

Re: Regular expression string searching & matching

From	Ben Hanson <jamin.hanson@googlemail.com>
Newsgroups	comp.compilers
Subject	Re: Regular expression string searching & matching
Date	2018-03-07 12:18 -0800
Organization	Compilers Central
Message-ID	<18-03-033@comp.compilers> (permalink)
References	<18-03-016@comp.compilers> <18-03-032@comp.compilers>

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I missed your question about non-greedy repeats.

Yes, it is possible. See build_dfa() in generator.hpp from lexertl.

Basically non-greedy transitions are snipped when building the dfa. I build a
regex syntax tree as suggested in the Dragon Book and I keep track of greedy
flags in the tree and that is passed down to partition/equivset.hpp and from
there to the generator. The thing you have to careful about is respecting that
the left side takes priority (i.e. the regex or sub-regex that came first).

Regards,

Ben

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Regular expression string searching & matching Clint O <clint.olsen@gmail.com> - 2018-03-04 01:37 -0800
  Re: Regular expression string searching & matching Ben Hanson <jamin.hanson@googlemail.com> - 2018-03-07 11:53 -0800
    Re: Regular expression string searching & matching Ben Hanson <jamin.hanson@googlemail.com> - 2018-03-07 12:18 -0800
    Re: Regular expression string searching & matching Clint O <clint.olsen@gmail.com> - 2018-03-08 22:53 -0800
      Re: Regular expression string searching & matching Clint O <clint.olsen@gmail.com> - 2018-03-10 00:57 -0800
        Re: Regular expression string searching & matching Ben Hanson <jamin.hanson@googlemail.com> - 2018-03-11 13:52 -0700
          Re: Regular expression string searching & matching Clint O <clint.olsen@gmail.com> - 2018-03-12 14:00 -0700
            Re: Regular expression string searching & matching Ben Hanson <jamin.hanson@googlemail.com> - 2018-03-13 11:30 -0700
              Re: Regular expression string searching & matching Clint O <clint.olsen@gmail.com> - 2018-03-17 16:52 -0700
              Re: Regular expression string searching & matching Clint O <clint.olsen@gmail.com> - 2018-03-18 19:23 +0000
              Re: Regular expression string searching & matching Clint O <clint.olsen@gmail.com> - 2018-03-20 17:23 +0000
                Re: Regular expression string searching & matching Clint O <clint.olsen@gmail.com> - 2018-03-22 17:46 +0000
          Re: Regular expression string searching & matching Ben Hanson <jamin.hanson@googlemail.com> - 2018-03-12 15:46 -0700
          Re: Regular expression string searching & matching Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2018-03-13 10:53 +0100
            Re: Regular expression string searching & matching Ben Hanson <jamin.hanson@googlemail.com> - 2018-03-13 14:23 -0700
      Re: Regular expression string searching & matching Ben Hanson <jamin.hanson@googlemail.com> - 2018-03-10 03:17 -0800

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