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From: Panicz Maciej Godek <godek.maciek@gmail.com>
To: Marco Maggi <marco.maggi-ipsu@poste.it>
Cc: guile-user@gnu.org
Subject: Re: Pattern matching issues
Date: Wed, 13 Jul 2011 12:42:09 +0200	[thread overview]
Message-ID: <CAMFYt2ZoHYU+06JMxXwbFtdAxMJz5=CZvB+i+w4oENNKZuvsUQ@mail.gmail.com> (raw)
In-Reply-To: <87wrfmzqjt.fsf@rapitore.luna>

2011/7/13 Marco Maggi <marco.maggi-ipsu@poste.it>:
> Panicz Maciej Godek wrote:
>
>> I've been  wondering if there  is a way to  represent this
>> sort of pattern for the pattern matcher provided by Wright
>> (and Guile).
>
> The syntax should be something like:
>
> (match '(Mr Hulot and I need a vacation)
>  ((?x ... 'need ?y ...)
>   (write (list ?x ?y))
>   (newline)))
>
> but at  present multiple ellipses  are not supported  at the
> same level  (that is in the  same list or  the same vector).
> It is  possible to do  it, but a  policy (greedy/non-greedy)
> must  be  adopted  to  solve  ambiguous cases  and  it  gets
> complicated.

I agree that it could get complicated for the ambiguous cases,
but it should at least be possible for the simple ones. I think that
the lack of this capability is a serious limitation of a pattern
matcher. I'm not well acquainted with regular expressions, but
I could try to resolve this issue upon the book that I'm currently
reading -- provided that there's no one dealing with it at the
moment

Regards
M.



  reply	other threads:[~2011-07-13 10:42 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-07-12 21:05 Pattern matching issues Panicz Maciej Godek
2011-07-12 22:21 ` Ludovic Courtès
2011-07-13  5:40 ` Marco Maggi
2011-07-13 10:42   ` Panicz Maciej Godek [this message]
2011-07-23 18:44 ` Linas Vepstas
2011-07-25 10:44   ` Andy Wingo

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