through bindings for Perl, Python and Haskell. It is the default regular expression engine in R. However if the project should be cross-platform, there would be necessary separate interface for each of the target platforms. Disadvantages Since other regular expression engines usually do not provide approximate matching ability, there is almost no concurrent implementation with which TRE could be compared. However there are a few things which programmers may wish to see implemented in future releases: a replacement mechanism for substituting matched text fragments (like in sed string processor and many modern implementations of regular expressions, including built into Perl or Java); opportunity to use another approximate matching algorithm (than Levenshtein's) for better typo value assessment (for example Soundex), or at least this algorithm to be improved to allow typos of the "swap" type (see Damerau–Levenshtein distance). See also Levenshtein automaton Comparison of regular expression engines Agrep References External links TRE - The free and portable approximate regular expression matching library Further reading Computer libraries Regular expressions Software using the BSD license