init array for immutable list

examples/pos/arrays.check

@@ -3,4 +3,5 @@ Some(world)
 None()
 Some(foo)
 Hello World,Hello World,Hello World,Hello World
-0,1,2,3,4
+0,1,2,3,4
+1,5,17

examples/pos/arrays.effekt

@@ -21,6 +21,9 @@ def main() = {
     val arrWithVals = initArray(4,"Hello World");
     println(arrWithVals)
 
-    val arrByF = initArray(5){ i => i};
-    println(arrByF)
+    val arrByF = arrayFromLoop(5){ i => i};
+    println(arrByF);
+
+    var arrByList = arrayFromList([1,5,17]);
+    println(arrByList)
 }

libraries/js/immutable/list.effekt

@@ -20,6 +20,14 @@ def foreach[A](l: List[A]) { f: A => Unit } : Unit = {
   }
 }
 
+def foreachIndex[T](list: List[T], i: Int){ f: (Int, T) => Unit}: Unit = {
+  list match {
+    case Nil() => ();
+    case Cons(head, tail) => f(i, head); foreachIndex(tail, i+1){f}
+
+  }
+}
+
 def map[A, B](l: List[A]) { f: A => B } : List[B] = {
   var acc = Nil[B]()
   l.foreach { el => acc = Cons(f(el), acc) }

libraries/js/mutable/array.effekt

@@ -15,12 +15,22 @@ def initArray[T](size: Int, default: T) : Array[T] = {
     return arr;
 }
 
-def initArray[T](size: Int) { index: Int => T}: Array[T] = {
+def arrayFromLoop[T](size: Int) { index: Int => T}: Array[T] = {
     val arr = emptyArray[T](size)
     each(0,arr.size()){ i=> put(arr, i, index(i))}
     return arr
 }
 
+def arrayFromList[T](list: List[T]): Array[T] = {
+  val listSize = list.size();
+  val arr = emptyArray(listSize);
+
+  foreachIndex(list, 0){(i, head) => put(arr, i, head)}
+  return arr;
+}
+
+
+
 extern pure def emptyArray[T](initialSize: Int): Array[T] =
   "(new Array(initialSize))"