Another update from ingydotnet^djgoku

Task/Levenshtein-distance/AppleScript/levenshtein-distance.applescript

@@ -0,0 +1,55 @@
+set dist to findLevenshteinDistance for "sunday" against "saturday"
+to findLevenshteinDistance for s1 against s2
+	script o
+		property l : s1
+		property m : s2
+	end script
+	if s1 = s2 then return 0
+	set ll to length of s1
+	set lm to length of s2
+	if ll = 0 then return lm
+	if lm = 0 then return ll
+	
+	set v0 to {}
+	
+	repeat with i from 1 to (lm + 1)
+		set end of v0 to (i - 1)
+	end repeat
+	set item -1 of v0 to 0
+	copy v0 to v1
+	
+	repeat with i from 1 to ll
+		-- calculate v1 (current row distances) from the previous row v0
+		
+		-- first element of v1 is A[i+1][0]
+		--   edit distance is delete (i+1) chars from s to match empty t
+		set item 1 of v1 to i
+		--  use formula to fill in the rest of the row
+		repeat with j from 1 to lm
+			if item i of o's l = item j of o's m then
+				set cost to 0
+			else
+				set cost to 1
+			end if
+			set item (j + 1) of v1 to min3 for ((item j of v1) + 1) against ((item (j + 1) of v0) + 1) by ((item j of v0) + cost)
+		end repeat
+		copy v1 to v0
+	end repeat
+	return item (lm + 1) of v1
+end findLevenshteinDistance
+
+to min3 for anInt against anOther by theThird
+	if anInt < anOther then
+		if theThird < anInt then
+			return theThird
+		else
+			return anInt
+		end if
+	else
+		if theThird < anOther then
+			return theThird
+		else
+			return anOther
+		end if
+	end if
+end min3