List#append, wrapping erl.lists.append()

src/builtins/list.re

@@ -53,6 +53,12 @@ class List
   def join
     join("")
   end
+
+  # Returns a new list built by concatenating the two lists together to 
+  # produce a third list.
+  def append(other_list)
+    erl.lists.append(self, other_list)
+  end
 
   # Iterate over a list, successively calling the given block and returning
   # the receiver when done

test/builtins/list_test.re

@@ -20,6 +20,7 @@ module ListTest
       complex_replace_test(),
       reverse_test(), 
       join_test(),
+      append_test(),
       each_test(),
       map_test(),
       all_test(),
@@ -87,6 +88,13 @@ module ListTest
       ("1,2,3", [1,2,3].join(','))
     end
   end
+
+  # concatenates two lists together to form a third list
+  def append_test
+    TestHelper.expect(List, "is concatenated with another list") do
+      ([1,2,3,4,5,6], [1,2,3].append([4,5,6]))
+    end
+  end
 
   # iterates each element
   def each_test