On Fri, May 15, 2020 at 07:32:50PM -0700, Joseph Brenner wrote:
> Regex engines by their nature care a lot about order, but I
> occasionally want to relax that to match for multiple
> multicharacter subpatterns where the order of them doesn't
> matter.
>
> Frequently the simplest thing to do is just to just do multiple
> matches. Let's say you're looking for words that have a "qu" a
> "th" and also, say an "ea". This works:
>
> my $DICT = "/usr/share/dict/american-english";
> my @hits = $DICT.IO.open( :r ).lines.grep({/qu/}).grep({/th/}).grep({/ea/});
> say @hits;
> # [bequeath bequeathed bequeathing bequeaths earthquake earthquake's
> earthquakes]
Would something like this work for you?
/^ <?before .* "qu" > <?before .* "th" > <?before .* "ea" > /
> Where things get interesting is when you want a negated match of
> one of the subpatterns. One of the things I like about the first
> approach using multiple chained greps is that it's easy to do a
> reverse match. What if you want words with "qu" and "th" but
> want to *skip* ones with an "ea"?
>
> my @hits = $DICT.IO.open( :r
> ).lines.grep({/qu/}).grep({/th/}).grep({!/ea/});
> # [Asquith discotheque discotheque's discotheques quoth]
Maybe something like this? (note the "!" instead of "?")
/^ <?before .* "qu" > <?before .* "th" > <!before .* "ea" > /
G'luck,
Peter
--
Peter Pentchev r...@ringlet.net r...@debian.org p...@storpool.com
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