The OpenD Programming Language

EditOp

Encodes edit operations necessary to transform one sequence into another. Given sequences s (source) and t (target), a sequence of EditOp encodes the steps that need to be taken to convert s into t. For example, if s = "cat" and "cars", the minimal sequence that transforms s into t is: skip two characters, replace 't' with 'r', and insert an 's'. Working with edit operations is useful in applications such as spell-checkers (to find the closest word to a given misspelled word), approximate searches, diff-style programs that compute the difference between files, efficient encoding of patches, DNA sequence analysis, and plagiarism detection.

Values

ValueMeaning
none'n'

Current items are equal; no editing is necessary.

substitute's'

Substitute current item in target with current item in source.

insert'i'

Insert current item from the source into the target.

remove'r'

Remove current item from the target.

Examples

with(EditOp)
{
    assert(levenshteinDistanceAndPath("foo", "foobar")[1] == [none, none, none, insert, insert, insert]);
    assert(levenshteinDistanceAndPath("banana", "fazan")[1] == [substitute, none, substitute, none, none, remove]);
}

Meta