Added Array#extract_options! to encapsulate the pattern of getting an options hash out of a variable number of parameters (closes #8759) [norbert]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@7217 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activesupport/CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* Added Array#extract_options! to encapsulate the pattern of getting an options hash out of a variable number of parameters #8759 [norbert].
+
 * Let alias_attribute work with attributes with initial capital letters (legacy columns etc).  Closes #8596 [mpalmer]
 
 * Added Hash#except which is the inverse of Hash#slice -- return the hash except the keys that are specified [DHH]

activesupport/lib/active_support/core_ext/array.rb

@@ -1,7 +1,9 @@
 require File.dirname(__FILE__) + '/array/conversions'
 require File.dirname(__FILE__) + '/array/grouping'
+require File.dirname(__FILE__) + '/array/extract_options'
 
 class Array #:nodoc:
   include ActiveSupport::CoreExtensions::Array::Conversions
   include ActiveSupport::CoreExtensions::Array::Grouping
+  include ActiveSupport::CoreExtensions::Array::ExtractOptions
 end

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

@@ -0,0 +1,19 @@
+module ActiveSupport #:nodoc:
+  module CoreExtensions #:nodoc:
+    module Array #:nodoc:
+      module ExtractOptions
+        # Extract options from a set of arguments. Removes and returns the last element in the array if it's a hash, otherwise returns a blank hash.
+        #
+        #   def options(*args)
+        #     args.extract_options!
+        #   end
+        #
+        #   options(1, 2)           # => {}
+        #   options(1, 2, :a => :b) # => {:a=>:b}
+        def extract_options!
+          last.is_a?(::Hash) ? pop : {}
+        end
+      end
+    end
+  end
+end

activesupport/test/core_ext/array_ext_test.rb

@@ -191,3 +191,12 @@ class ArrayToXmlTests < Test::Unit::TestCase
     assert xml.include?(%(<count>2</count>)), xml
   end
 end
+
+class ArrayExtractOptionsTests < Test::Unit::TestCase
+  def test_extract_options
+    assert_equal({}, [].extract_options!)
+    assert_equal({}, [1].extract_options!)
+    assert_equal({:a=>:b}, [{:a=>:b}].extract_options!)
+    assert_equal({:a=>:b}, [1, {:a=>:b}].extract_options!)
+  end
+end