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Re: on parrot strings
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From:
Jarkko Hietaniemi
Date:
January 18, 2002 14:28
Subject:
Re: on parrot strings
Message ID:
20020119002815.W25478@alpha.hut.fi
On Fri, Jan 18, 2002 at 02:22:49PM -0800, Steve Fink wrote:
> On Sat, Jan 19, 2002 at 12:11:06AM +0200, Jarkko Hietaniemi wrote:
> > Complement of an inversion list is neat: insert 0 at the beginning
> > (and append max+1), unless there already is one, in which case delete
> > the 0 (and shift the list and delete the max+1). Again, O(N).
> > (One could of course have a bit for a 'negative character class',
> > but that would in turn complicate the computations.)
>
> If we have hybrid notation, we'll be stuck with not only a bit for
> that, but also a complete expression tree for character classes.
> (Which is necessary if we use a Unicode library that only exposes
> property test functions, not numeric ranges.)
>
> We *do* want to have (with some notation)
> [[:digit:]\p{FunkyLooking}aeiou except 7], right?
Of course. But that is all resolvable in regex compile time.
No expression tree needed.
[[:digit:]\p{FunkyLooking}aeiou$FooBar] is an ickier case,
but even there the constant parts can be resolved in regex
compile time. (Don't say "locales" or I'll ha've have to hurt you,
for your own good. :-)
--
$jhi++; # http://www.iki.fi/jhi/
# There is this special biologist word we use for 'stable'.
# It is 'dead'. -- Jack Cohen
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