NOTE: An application using a library for regular expression support does not necessarily offer the full set of features of the library, e.g. GNU Grep which uses PCRE does not offer lookahead support, though PCRE does.
^Non-greedy quantifiers match as few characters as possible, instead of the default as many. Note that many older, pre-POSIX engines were non-greedy and didn't have greedy quantifiers at all
^Shy groups, also called non-capturing groups cannot be referred to with backreferences; non-capturing groups are used to speed up matching where the groups content needs not be accessed later.
^Backreferences enable referring to previously matched groups in later parts of the regex and/or replacement string (where applicable). For instance, ([ab]+)\1 matches "abab" but not "abaab"
^Similar to back references but with names instead of indices
^ abcdefgUnicode property support may be incomplete (products are continuously updated!). **All will be incomplete** when a new Unicode revision is released *until* they are updated to comply.
^ abMeans the format can be used internally without explicit conversion
^Supports Unicode 4.0 standard from 2003; latest plans for JDK7 include Unicode 6.0 (2011) support [1]
^Implementation uses original UCS-2 support/features, so it only recognizes 64K chars total (vs UTF-16's 1,112,064 characters). A Microsoft developer-representative answered a bug report on this as "will not fix" in 2010). [2].
Tags: Comparison of regular expression engines, Integration of Computers, 482, Comparison of regular expression engines This is a comparison of regular expression engines, Contents Libraries 2 Languages 3 Language features 3.1 Part 3.2 Part 2 4 API features 5 See also 6 External links Libraries List of regular expression libraries Name Official website Programming language Software license Boost, Regex [ Note ] Boost C Libraries C Boost Boost.Xpressive Boost C Librar, Comparison of regular expression engines, English, Instruction Examples, Tutorials, Reference, Books, Guide regular tuition program, pts-ptn.net