Article View: comp.editors
Article #3208Re: pattern matches
From: Ge' Weijers
Date: Thu, 07 Jul 1988 11:27
Date: Thu, 07 Jul 1988 11:27
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1330 bytes
In article <18838@cornell.UUCP>, blandy@marduk.cs.cornell.edu (Jim Blandy) writes:
> I do think negation is well-defined; using the proposed syntax, (pat)^
> matches any string pat would not. Since the set of strings matched by
> pat is (presumably) well-defined, the set for (pat)^ is too.
>
> About the claim that "negation should be trivial, since it only entails
> flipping the accept/reject-ingness of the states in the automaton...":
>
The complement of a regular expression is a regular expression, although the
derivation is not quite trivial. Matching a (xyz)^ is possible in theory
and in practice. So if someone can whip up some code to generate
the complement.....
--
Ge' Weijers, Informatics dept., Nijmegen University, the Netherlands
UUCP: {uunet!,}mcvax!kunivv1!hobbit!ge
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<295@hobbit.sci.kun.nl>Path:
arc1-ca.pugleaf.net!utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!pasteur!ucbvax!decwrl!sun!pitstop!sundc!seismo!uunet!mcvax!kunivv1!hobbit!geReferences:
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!pasteur!ucbvax!decwrl!sun!pitstop!sundc!seismo!uunet!mcvax!kunivv1!hobbit!ge From: ge@hobbit.sci.kun.nl (Ge' Weijers) Newsgroups: comp.editors Subject: Re: pattern matches Summary: inverse of pattern should be possible Message-ID: <295@hobbit.sci.kun.nl> Date: 7 Jul 88 11:27:28 GMT References: <427@grand.UUCP> <37200009@m.cs.uiuc.edu> <18838@cornell.UUCP> Organization: University of Nijmegen, The Netherlands. Lines: 16