Merge pull request #368 from judofyr/array-last

Implement Array#last properly

fabfile/travis.py

@@ -140,6 +140,7 @@ def run_specs(binary, prefix=""):
         "core/array/delete_at_spec.rb",
         "core/array/empty_spec.rb",
         "core/array/frozen_spec.rb",
+        "core/array/last_spec.rb",
         "core/array/length_spec.rb",
         "core/array/plus_spec.rb",
         "core/array/push_spec.rb",

topaz/objects/arrayobject.py

@@ -2,6 +2,7 @@
 
 from rpython.rlib.listsort import TimSort
 
+from topaz.coerce import Coerce
 from topaz.module import ClassDef, check_frozen
 from topaz.modules.enumerable import Enumerable
 from topaz.objects.objectobject import W_Object
@@ -333,7 +334,16 @@ def first
     """)
 
     @classdef.method("last")
-    def method_last(self, space):
+    def method_last(self, space, w_count=None):
+        if w_count is not None:
+            count = Coerce.int(space, w_count)
+            if count < 0:
+                raise space.error(space.w_ArgumentError, "negative array size")
+            start = len(self.items_w) - count
+            if start < 0:
+                start = 0
+            return space.newarray(self.items_w[start:])
+
         if len(self.items_w) == 0:
             return space.w_nil
         else: