Added simple arrays.

examples/arrays.fun

@@ -0,0 +1,47 @@
+// Arrays basics
+arr = [1, 2, 3]
+print(arr)                 // -> [1, 2, 3]
+print(arr[0] + arr[1])     // -> 3
+
+// mutate last element
+arr[2] = arr[2] + 10
+print(arr)                 // -> [1, 2, 13]
+
+// Sum elements with while (fixed length)
+number i = 0
+number sum = 0
+number len = 3
+while i < len
+  sum = sum + arr[i]
+  i = i + 1
+print(sum)                 // -> 16
+
+// Fill with squares using for in range
+arr = [0, 0, 0, 0, 0]
+for i in range(0, 5)
+  arr[i] = i * i
+print(arr)                 // -> [0, 1, 4, 9, 16]
+
+// Nested arrays (matrix)
+matrix = [[1, 2], [3, 4], [5, 6]]
+print(matrix)              // -> [[1, 2], [3, 4], [5, 6]]
+print(matrix[1][0])        // -> 3
+
+// Function that mutates an array in place (first 3 elements)
+fun scale3(a, s)
+  number i = 0
+  while i < 3
+    a[i] = a[i] * s
+    i = i + 1
+
+arr = [2, 4, 6]
+scale3(arr, 5)
+print(arr)                 // -> [10, 20, 30]
+
+// Function that returns an array
+fun pair(x, y)
+  return [x, y]
+
+p = pair(7, 9)
+print(p)                   // -> [7, 9]
+print(p[1])                // -> 9