Perl Compatible Regular Expressions (PCRE) is a regular expression C library inspired by Perl's external interface, written by Philip Hazel. PCRE's syntax is much more powerful and flexible than either of the POSIX regular expression flavors and many classic regular expression libraries. The name is misleading, because PCRE and Perl each have capabilities not shared by the other.
The PCRE library is incorporated into a number of prominent open-source programs, such as the Apache HTTP Server and the PHP and R scripting languages; and can be incorporated in proprietary software too (BSD license). 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 using configure and make (typical of Unix-like environments), as well as in Unix, Windows and other environments using CMake. Numerous default settings are chosen at build time. In addition to the PCRE library, a POSIX C wrapper, a Google-contributed native C++ wrapper, several test programs, and the utility program pcregrep are also included in the distribution and are built in tandem with the library. The PCRE library provides matching only; the C++ wrapper, if used, adds multiple match and replacement functionality.
Unless the "NoRecurse" PCRE build option (aka "--disable-stack-for-recursion") is chosen, adequate stack space must be allocated to PCRE by the calling application or operating system. The amount of stack needed varies for each pattern. For example, to complete the tests provided with pcretest, 8 MB of stack space would be needed. While PCRE's documentation cautions that the "NoRecurse" build option makes PCRE slower than the alternative, using it avoids entirely the issue of stack overflows.
Read more about Perl Compatible Regular Expressions: Features, Differences From Perl
Famous quotes containing the words compatible, regular and/or expressions:
“As to happiness in this life it is hardly compatible with that diminished respect which ever attends the relinquishing of labour.”
—Anthony Trollope (1815–1882)
“My attitude toward punctuation is that it ought to be as conventional as possible. The game of golf would lose a good deal if croquet mallets and billiard cues were allowed on the putting green. You ought to be able to show that you can do it a good deal better than anyone else with the regular tools before you have a license to bring in your own improvements.”
—Ernest Hemingway (1899–1961)
“Let it be signified to me through any channel ... that the possession of the Floridas would be desirable to the United States, and in sixty days it will be accomplished.
...penned in the language of truth, and divested of those expressions of servility which would persuade his majesty that we are asking favors and not rights.”
—Thomas Jefferson (1743–1826)