Re: FYI: Regex paper for UTC

From: Hans Aberg (
Date: Sun Oct 14 2007 - 04:21:05 CDT

  • Next message: Hans Aberg: "Re: FYI: Regex paper for UTC"

    On 14 Oct 2007, at 10:45, Philippe Verdy wrote:

    > According to what is proposed in the latest UTC paper, that
    > describes the 10
    > rewrite rules, there's nothing that what isdescribed there that I
    > don't
    > support as well; it's just that I perform the rewrites in the reverse
    > direction, without changing the complete set of returned matches.
    > You may consider implementing the 10 rewrites the way it is
    > described in the
    > recent UTC paper, but I'm sure that it is equivalent to performing the
    > reverse operations (using only 3 rewrite rules instead of 10,
    > including one
    > that is common about cancelling double negations, which is trivial,
    > so the
    > differences are in 2 rewrites against 8, and I suppress two
    > operators using
    > only alternations and no intersections or differences).

    If this refers to the link that posted at the start of this thread,
    you need to describe a theory that makes it is clear what the REs are
    supposed to match. It does not suffice to say "a I sure" - the reader
    should be able to follow it.

    The normal thing is that a RE produces a language. If you want
    special ways to match it, be from that language or otherwise, that
    must also be described in a theoretical manner.

    I think that the language set operations amiss might be added
    (intersection and complement) might be added, which can be reduced to
    ordinary REs. If there are other operators to be defined, they need
    to be described clearly in a theoretical manner, so one is not left
    guessing from a few examples.

       Hans Åberg

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