Perl Compatible Regular Expressions

Perl Compatible Regular Expressions (PCRE) is a library written in C, which implements a regular expression engine, inspired by the capabilities of the Perl programming language. Philip Hazel started writing PCRE in summer 1997. PCRE's syntax is much more powerful and flexible than either of the POSIX regular expression flavors and than that of many other regular-expression libraries. Perl Compatible Regular Expressions (PCRE) is a library written in C, which implements a regular expression engine, inspired by the capabilities of the Perl programming language. Philip Hazel started writing PCRE in summer 1997. PCRE's syntax is much more powerful and flexible than either of the POSIX regular expression flavors and than that of many other regular-expression libraries. While PCRE originally aimed at feature-equivalence with Perl, the two implementations are not fully equivalent. During the PCRE 7.x and Perl 5.9.x phase, the two projects have coordinated development, with features being ported between them in both directions. A number of prominent open-source programs, such as the Apache and Nginx HTTP Servers, and the PHP and R scripting languages, incorporate the PCRE library; proprietary software can do likewise, as the library is BSD licensed. As of Perl 5.10, PCRE is also available as a replacement for Perl's default regular expression engine through the re::engine::PCRE module. The library can be built on Unix, Windows, and several other environments. PCRE is distributed with a POSIX C wrapper, a native C++ wrapper, several test programs, and the utility program pcregrep built in tandem with the library. Differences between PCRE and Perl (as of Perl 5.9.4) include but are not limited to: With the exception of the above points PCRE is capable of passing the tests in the Perl 't/op/re_tests' file, one of the main syntax level regression tests for Perl's regular expression engine.