The Levenshtein distance is a metric for measuring the amount of difference between two sequences (i.e., the so called edit distance). The Levenshtein distance between two sequences is given by the minimum number of operations needed to transform one sequence into the other, where an operation is an insertion, deletion, or substitution of a single element.
The two sequences can be two strings, two arrays, or two other objects responding to :each. All sequences are by generic (fast) C code.
All objects in the sequences should respond to :hash and :eql?.