levenshtein.go

package argparse

func decideMatch(target string, candidates []string) []string {
	if len(candidates) <= 0 {
		return []string{} // no match at all
	}
	ldArray := make([]int, len(candidates))
	for i, c := range candidates {
		ldArray[i] = levDistance(target, c)
	}
	match := min(ldArray...)
	if match >= len(target) { // too many diff
		return []string{}
	}
	matchCandidates := make(map[int][]string)
	var matchKeys []int
	for i, ld := range ldArray {
		if ld == match {
			wordL := len(candidates[i])
			matchKeys = append(matchKeys, wordL)
			matchCandidates[wordL] = append(matchCandidates[wordL], candidates[i])
		}
	}
	return matchCandidates[min(matchKeys...)]
}

func levDistance(a, b string) int {
	la := len(a)
	lb := len(b)
	matrix := make([][]int, la+1)
	for i := range matrix {
		matrix[i] = make([]int, lb+1)
	}
	for i := 0; i <= la; i += 1 {
		matrix[i][0] = i
	}
	for i := 0; i <= lb; i += 1 {
		matrix[0][i] = i
	}
	for i := 1; i <= la; i += 1 {
		for j := 1; j <= lb; j += 1 {
			cost := 1
			if a[i-1] == b[j-1] {
				cost = 0
			}
			matrix[i][j] = min(
				matrix[i-1][j-1]+cost,
				matrix[i][j-1]+1,
				matrix[i-1][j]+1)
		}
	}
	return matrix[la][lb]
}

func _min(a, b int) int {
	if a < b {
		return a
	}
	return b
}

func min(candidate ...int) int {
	if len(candidate) == 1 {
		return candidate[0]
	}
	return _min(candidate[0], min(candidate[1:]...))
}