Bowling kata

.gitignore

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+target
+.idea
+.idea_modules

bowling/build.sbt

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+name := "bowling"
+
+version := "1.0"
+
+scalaVersion := "2.9.1"
+
+libraryDependencies ++= Seq(
+    "org.specs2" %% "specs2" % "1.8")
+
+resolvers ++= Seq("snapshots" at "http://oss.sonatype.org/content/repositories/snapshots",
+                    "releases"  at "http://oss.sonatype.org/content/repositories/releases")

bowling/src/main/scala/bowling.scala

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+object Bowling {
+  private def scoreValue(score: Char): Int = {
+    score match {
+      case 'x' => 10
+      case '-' => 0
+      case digit => digit.toString.toInt
+    }
+  }
+
+  private def scoreFrames(frames: List[Char]): List[Int] = {
+    frames match {
+      case Nil => List()
+      case 'x' :: _ :: '/' :: _ =>
+        20 :: scoreFrames(frames.drop(1)) // strike + spare == 20
+      case 'x' :: _ => 
+        frames.take(3).map(scoreValue).sum :: scoreFrames(frames.drop(1))
+      case _ :: '/' :: nextRoll :: _ =>
+        (10 + scoreValue(nextRoll)) :: scoreFrames(frames.drop(2))
+      case _ =>
+        frames.take(2).map(scoreValue).sum :: scoreFrames(frames.drop(2))
+    }
+  }
+
+  def score(scores: String): Int = {
+    assert(scores.matches("[0-9x/-]{10,22}"), "Invalid scores!")
+    scoreFrames(scores.toList).take(10).sum // don't count bonus frames as normal frames
+  }
+
+  def main(args: Array[String]): Unit = {
+    print("Enter frame scores: ")
+    val result = score(readLine())
+    println("Total score: " + result)
+  }
+}

bowling/src/test/scala/BowlingSpec.scala

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+import org.specs2.mutable._
+
+class BowlingSpec extends Specification {
+  "For an open frame it" should {
+    "add the points of the two rolls" in {
+      Bowling.score("11--------") must_== 2
+    }
+  }
+
+  "For a spare it" should {
+    "award the next frame as bonus" in {
+      Bowling.score("9/3-------") must_== 16
+    }
+  }
+
+  "For a strike it" should {
+    "award the next 2 frames as bonus" in {
+      Bowling.score("x34-------") must_== 24
+    }
+  }
+  "For an entire game it" should {
+      "score a perfect game with 300" in {
+        Bowling.score("xxxxxxxxxxxx") must_== 300
+      }
+
+      "give 0 points for all in gutter" in {
+        Bowling.score("----------") must_== 0
+      }
+
+    "score a game of 9s with 90" in {
+        Bowling.score("9-9-9-9-9-9-9-9-9-9-") must_== 90
+    }
+
+    "score a game of 5-spares with 150" in {
+      Bowling.score("5/5/5/5/5/5/5/5/5/5/5") must_== 150
+    }
+    "score an average game with 168" in {
+      Bowling.score("x7/729/xxx236/7/3") must_== 168
+    }
+  }
+}
+
+