sentence: however there are few things which programmers may wish to be 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 ) .