Initial data commit

Task/Forward-difference/Wren/forward-difference.wren

@@ -0,0 +1,18 @@
+import "/fmt" for Fmt
+
+var forwardDiff = Fn.new { |a, order|
+    if (order < 0) Fiber.abort("Order must be a non-negative integer.")
+    if (a.count == 0) return
+    Fmt.print(" 0: $5d", a)
+    if (a.count == 1) return
+    if (order == 0) return
+    for (o in 1..order) {
+        var b = List.filled(a.count-1, 0)
+        for (i in 0...b.count) b[i] = a[i+1] - a[i]
+        Fmt.print("$2d: $5d", o, b)
+        if (b.count == 1) return
+        a = b
+    }
+}
+
+forwardDiff.call([90, 47, 58, 29, 22, 32, 55, 5, 55, 73], 9)