magnet.lagun

levenshtein

(levenshtein str1 str2)(levenshtein row-nr prevrow str1 str2)
Calculate the Levenshtein distance between two strings.

nextelt

(nextelt char1 char2 prevrow thisrow position)
Given two characters, the previous row, and a row we are
building, determine out the next element for this row.

nextrow

(nextrow char1 str2 prevrow thisrow)
Based on the next character from string1 and the whole of string2
calculate the next row. Initially thisrow contains one number.