devel/tre 0.8.0 NetBSD

TRE is a lightweight, robust, and efficient POSIX compliant regexp matching library with some exciting features such as approximate (fuzzy) matching.

At the core of TRE is a new algorithm for regular expression matching with submatch addressing. The algorithm uses linear worst-case time in the length of the text being searched, and quadratic worst-case time in the length of the used regular expression. In other words, the time complexity of the algorithm is O(M2N), where M is the length of the regular expression and N is the length of the text. The used space is also quadratic on the length of the regex, but does not depend on the searched string. This quadratic behaviour occurs only on pathological cases which are probably very rare in practice.

TRE includes a version of the agrep (approximate grep) command line tool for approximate regexp matching in the style of grep. Unlike other agrep implementations (like the one by Sun Wu and Udi Manber from University of Arizona available here) TRE agrep allows full regexps of any length, any number of errors, and non-uniform costs for insertion, deletion and substitution.