Introduce Array.wrap(foo) to wrap the argument in an array unless it's already...

Introduce Array.wrap(foo) to wrap the argument in an array unless it's already an array. Wraps nil as an empty array. Use instead of Array(foo) and foo.to_a since they treat String as Enumerable.

activesupport/CHANGELOG

+*Edge*
+
+* Introduce Array.wrap(foo) to wrap the argument in an array unless it's already an array. Wraps nil as an empty array. Use instead of Array(foo) and foo.to_a since they treat String as Enumerable.  [Jeremy Kemper]
+
+
 *2.3.0 [RC1] (February 1st, 2009)*
 
 * TimeWithZone#xmlschema accepts optional fraction_digits argument [#1725 state:resolved] [Nicholas Dainty]

activesupport/lib/active_support/core_ext/array.rb

@@ -3,6 +3,7 @@
 require 'active_support/core_ext/array/extract_options'
 require 'active_support/core_ext/array/grouping'
 require 'active_support/core_ext/array/random_access'
+require 'active_support/core_ext/array/wrapper'
 
 class Array #:nodoc:
   include ActiveSupport::CoreExtensions::Array::Access
@@ -10,4 +11,5 @@ class Array #:nodoc:
   include ActiveSupport::CoreExtensions::Array::ExtractOptions
   include ActiveSupport::CoreExtensions::Array::Grouping
   include ActiveSupport::CoreExtensions::Array::RandomAccess
+  extend ActiveSupport::CoreExtensions::Array::Wrapper
 end

activesupport/lib/active_support/core_ext/array/wrapper.rb

+module ActiveSupport #:nodoc:
+  module CoreExtensions #:nodoc:
+    module Array #:nodoc:
+      module Wrapper
+        # Wraps the object in an Array unless it's an Array.
+        def wrap(object)
+          case object
+          when nil
+            []
+          when self
+            object
+          else
+            [object]
+          end
+        end
+      end
+    end
+  end
+end

activesupport/test/core_ext/array_ext_test.rb

@@ -302,3 +302,27 @@ def test_random_element_from_array
     assert_equal 2, [1, 2, 3].rand
   end
 end
+
+class ArrayWrapperTests < Test::Unit::TestCase
+  def test_array
+    ary = %w(foo bar)
+    assert_same ary, Array.wrap(ary)
+  end
+
+  def test_nil
+    assert_equal [], Array.wrap(nil)
+  end
+
+  def test_object
+    o = Object.new
+    assert_equal [o], Array.wrap(o)
+  end
+
+  def test_string
+    assert_equal ["foo"], Array.wrap("foo")
+  end
+
+  def test_string_with_newline
+    assert_equal ["foo\nbar"], Array.wrap("foo\nbar")
+  end
+end