Programming Perl, 4th Edition

Alternate Engines

Starting with v5.10, you can even swap out Perl’s entire regex engine and replace it with an alternate pattern-matching library. The underlying mechanics that make this possible are documented in the perlreapi manpage. It’s pretty tough reading, meant for seriously hardcore hackers only.

But you may be in luck. Thanks to CPAN, Perl plug-ins for the alternate regex engine of your choice may already exist. When you use these, you write your patterns normally and, come time to execute them, the alternate engine takes charge. Table 5-18 shows some CPAN modules that let you use other languages’ regex engines in your Perl code (as they exist on CPAN in autumn 2011). There may be more by the time you read this, so look around.

Table 5-18. Alternate regex engines

Module	Description	Version	Updated	Current Maintainer
re::engine::LPEG	The LPEG regex engine	0.05	2010-07-09	François Perrad
re::engine::RE2	Russ Cox’s RE2 regex engine	0.08	2011-04-22	David Leadbeater
re::engine::Plugin	General API for writing custom regex engines	0.09	2011-04-05	Vincent Pit
re::engine::Plan9	Regexes from Plan9!	0.16	2010-03-31	Ævar Arnfjörð Bjarmason
re::engine::Oniguruma	Ruby’s Oniguruma regex engine	0.05	2011-07-10
re::engine::Lua	Lua’s regex engine	0.06	2008-12-20	François Perrad
re::engine::PCRE	Phil Hazel’s Perl-Compatible RegEx engine	0.17	2011-Jan-29	Ævar Arnfjörð Bjarmason

(Notice anything about those authors? More than ...