From 476583c90a47cad62f992ab0b845ebf2897cb47d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=A9my=20Zurcher?= <jeremy@asynk.ch>
Date: Wed, 3 Apr 2013 22:18:48 +0200
Subject: Scala : cleanup, Scala : add sumCurry

---
 Scala/sandbox/curry.scala     | 30 ++++++++++++++++++++++++++++++
 Scala/sandbox/main.scala      |  1 +
 Scala/sandbox/recursion.scala | 11 ++++++-----
 Scala/sandbox/sqrt.scala      |  4 +++-
 Scala/sandbox/sum.scala       | 14 --------------
 5 files changed, 40 insertions(+), 20 deletions(-)
 create mode 100644 Scala/sandbox/curry.scala
 delete mode 100644 Scala/sandbox/sum.scala

diff --git a/Scala/sandbox/curry.scala b/Scala/sandbox/curry.scala
new file mode 100644
index 0000000..910de62
--- /dev/null
+++ b/Scala/sandbox/curry.scala
@@ -0,0 +1,30 @@
+
+object Curry {
+
+  // high order function
+  def sum(f: Int => Int, a: Int, b: Int) = {
+    def loop(a: Int, acc: Int): Int  =
+      if (a > b) acc
+      else loop(a + 1, f(a) + acc)
+    loop(a, 0)
+  }
+
+  // curry version: this function return an (Int, Int) => Int function
+  def sumCurry(f: Int => Int): (Int, Int) => Int = {
+    def sumF(a: Int, b: Int): Int  =
+      if (a > b) 0
+      else f(a) + sumF(a + 1, b)
+    sumF
+  }
+
+  def sumInts   = sumCurry(x => x)
+  def sumCubes  = sumCurry(x => x * x)
+
+  def run = {
+    println("Curry")
+    println(sum(x => x * x, 3, 5))
+    println(sumInts(3, 5))
+    println(sumCubes(3, 5))
+  }
+
+}
diff --git a/Scala/sandbox/main.scala b/Scala/sandbox/main.scala
index e770ece..7a0b791 100644
--- a/Scala/sandbox/main.scala
+++ b/Scala/sandbox/main.scala
@@ -3,5 +3,6 @@ object Main extends App {
 
   Sqrt.run
   Recursion.run
+  Curry.run
 
 }
diff --git a/Scala/sandbox/recursion.scala b/Scala/sandbox/recursion.scala
index e7c29a5..5488aea 100644
--- a/Scala/sandbox/recursion.scala
+++ b/Scala/sandbox/recursion.scala
@@ -8,15 +8,11 @@ object Recursion {
   def gcd(a: Int, b: Int): Int =
     if (b == 0) a else gcd(b, a % b)
 
-  println(gcd(21, 56))
-
   // there is still the multiplication to be performed
   // -> the stack frame can't be reused
   def fact(n: Int): Int =
     if (n == 0) 1 else n * fact(n - 1)
 
-  println(fact(4))
-
   // tail recursive version of factorial
   def factr(n: Int): Int = {
     def factIter(acc: Int, n: Int): Int =
@@ -24,6 +20,11 @@ object Recursion {
     factIter(1, n)
   }
 
-  def run = println(factr(4))
+  def run = {
+    println("Recursion")
+    println(gcd(21, 56))
+    println(fact(4))
+    println(factr(4))
+  }
 
 }
diff --git a/Scala/sandbox/sqrt.scala b/Scala/sandbox/sqrt.scala
index 2544425..c76ee00 100644
--- a/Scala/sandbox/sqrt.scala
+++ b/Scala/sandbox/sqrt.scala
@@ -18,11 +18,13 @@ object Sqrt {
     sqrtIter(1.0)
   }
 
-  def run =
+  def run = {
+    println("Sqrt")
     println(sqrt(2))
     println(sqrt(0.001))
     println(sqrt(0.1e-20))
     println(sqrt(1.0e20))
     println(sqrt(1.0e50))
+  }
 
 }
diff --git a/Scala/sandbox/sum.scala b/Scala/sandbox/sum.scala
deleted file mode 100644
index a09f26b..0000000
--- a/Scala/sandbox/sum.scala
+++ /dev/null
@@ -1,14 +0,0 @@
-
-object Sum {
-
-  def sum (f: Int => Int, a: Int, b: Int) = {
-    def loop(a: Int, acc: Int): Int  =
-      if (a > b) acc
-      else loop(a + 1, f(a) + acc)
-    loop(a, 0)
-  }
-
-  def run =
-    println(sum(x => x * x, 3, 5))
-
-}
-- 
cgit v1.1-2-g2b99