Merge pull request #103 from Philippus/add-azerty-keyboard

Add azerty

README.md

@@ -9,7 +9,7 @@
 Osita is an implementation of the [Optimal String Alignment distance](https://en.wikipedia.org/wiki/Damerau%E2%80%93Levenshtein_distance#Optimal_string_alignment_distance)
 algorithm. It implements the standard version of the algorithm and an extension of it where the substitution cost has
 been replaced by a function which calculates the keyboard distance between characters using the Euclidean distance
-between keys on a QWERTY-keyboard.
+between keys on a QWERTY or AZERTY-keyboard.
 You can also supply your own substitution cost function.
 
 ## Installation
@@ -26,7 +26,7 @@ import nl.gn0s1s.osita.Osita._
 
 osa("abcde", "abcde") // val res0: Double = 0.0
 osa("abcde", "abcd") // val res1: Double = 1.0
-osaWithSubstitutionCost("abc", "agc")(weightedKeyboardSubstitutionCost) // val res2: Double = 1.118033988749895
+osaWithSubstitutionCost("abc", "agc")(qwertySubstitutionCost) // val res2: Double = 1.118033988749895
 
 ```
 

src/main/scala/nl/gn0s1s/osita/Osita.scala

@@ -13,11 +13,19 @@ object Osita {
       .map(_.toCharArray)
   }
 
+  private val azertyKeyboardGrid: Array[Array[Char]] = {
+    """azertyuiop
+      |qsdfghjklm
+      |wxcvbn""".stripMargin
+      .split('\n')
+      .map(_.toCharArray)
+  }
+
   private def simpleSubstitutionCost[A](a: A, b: A): Double =
     if (a == b) 0.0D else 1.0D
 
-  private def findPos(c: Char): (Double, Double) = {
-    val t      = qwertyKeyboardGrid.map(row => row.indexOf(c))
+  private def findPos(c: Char, keyboardGrid: Array[Array[Char]]): (Double, Double) = {
+    val t      = keyboardGrid.map(row => row.indexOf(c))
     val column = t.max
     val row    = t.indexOf(column)
     // compensate for the difference between rows on a keyboard
@@ -35,7 +43,21 @@ object Osita {
     def euclideanDistance(p1: (Double, Double), p2: (Double, Double)): Double =
       scala.math.sqrt(scala.math.pow(p1._1 - p2._1, 2) + scala.math.pow(p1._2 - p2._2, 2))
 
-    euclideanDistance(findPos(a), findPos(b))
+    euclideanDistance(findPos(a, qwertyKeyboardGrid), findPos(b, qwertyKeyboardGrid))
+  }
+
+  def qwertySubstitutionCost(a: Char, b: Char): Double = {
+    def euclideanDistance(p1: (Double, Double), p2: (Double, Double)): Double =
+      scala.math.sqrt(scala.math.pow(p1._1 - p2._1, 2) + scala.math.pow(p1._2 - p2._2, 2))
+
+    euclideanDistance(findPos(a, qwertyKeyboardGrid), findPos(b, qwertyKeyboardGrid))
+  }
+
+  def azertySubstitutionCost(a: Char, b: Char): Double = {
+    def euclideanDistance(p1: (Double, Double), p2: (Double, Double)): Double =
+      scala.math.sqrt(scala.math.pow(p1._1 - p2._1, 2) + scala.math.pow(p1._2 - p2._2, 2))
+
+    euclideanDistance(findPos(a, azertyKeyboardGrid), findPos(b, azertyKeyboardGrid))
   }
 
   // https://en.wikipedia.org/wiki/Damerau%E2%80%93Levenshtein_distance#cite_note-Boytsov-7

src/test/scala/nl/gn0s1s/osita/OsitaSuite.scala

@@ -45,4 +45,9 @@ class OsitaSuite extends ScalaCheckSuite {
   property("osaWithKeyboard counts transpositions correctly") {
     osaWithSubstitutionCost("abc", "acb")(weightedKeyboardSubstitutionCost) == 1
   }
+
+  property("osaWithKeyboard with azerty works") {
+    assertEquals(osaWithSubstitutionCost("mop", "nop")(qwertySubstitutionCost), 1D)
+    assertEquals(osaWithSubstitutionCost("mop", "nop")(azertySubstitutionCost), 2D)
+  }
 }