The Porter stemmer in Snowball is given below. This is an exact implementation of the algorithm described in the 1980 paper, unlike the other implementations distributed by the author, which have, and have always had, three small points of difference (clearly indicated) the original algorithm.-The Porter stemmer in Snowball is given below. This is an exact implementation of the algorithm described in the 1980 paper, unlike the other implementations distributed by the author, which have, and have always had, three small points of difference (clearly indicated)　the original algorithm.