Added Array#from and Array#to that behaves just from String#from and String#to [DHH]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@8224 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

4 files changed, 46 insertions, 0 deletions

diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG
index 1ecee37c46..c4886f37f7 100644
--- a/activesupport/CHANGELOG
+++ b/activesupport/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Added Array#from and Array#to that behaves just from String#from and String#to [DHH]
+
 * Fix that empty collections should be treated as empty arrays regardless of whitespace for Hash#from_xml #10255 [adamj]
 
 * Time#time_with_datetime_fallback, Time#to_datetime, Date#to_datetime and String#to_datetime honor Ruby's default calendar reform setting. #10201 [Geoff Buesing]
diff --git a/activesupport/lib/active_support/core_ext/array.rb b/activesupport/lib/active_support/core_ext/array.rb
index 4c973488a5..cc0a1ebc12 100644
--- a/activesupport/lib/active_support/core_ext/array.rb
+++ b/activesupport/lib/active_support/core_ext/array.rb
@@ -1,9 +1,11 @@
+require 'active_support/core_ext/array/access'
 require 'active_support/core_ext/array/conversions'
 require 'active_support/core_ext/array/extract_options'
 require 'active_support/core_ext/array/grouping'
 require 'active_support/core_ext/array/random_access'
 
 class Array #:nodoc:
+  include ActiveSupport::CoreExtensions::Array::Access
   include ActiveSupport::CoreExtensions::Array::Conversions
   include ActiveSupport::CoreExtensions::Array::ExtractOptions
   include ActiveSupport::CoreExtensions::Array::Grouping
diff --git a/activesupport/lib/active_support/core_ext/array/access.rb b/activesupport/lib/active_support/core_ext/array/access.rb
new file mode 100644
index 0000000000..fce319d3c6
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/array/access.rb
@@ -0,0 +1,28 @@
+module ActiveSupport #:nodoc:
+  module CoreExtensions #:nodoc:
+    module Array #:nodoc:
+      # Makes it easier to access parts of an array.
+      module Access
+        # Returns the remaining of the array from the +position+.
+        #
+        # Examples: 
+        #   %w( a b c d ).from(0)  # => %w( a b c d )
+        #   %w( a b c d ).from(2)  # => %w( c d )
+        #   %w( a b c d ).from(10) # => nil
+        def from(position)
+          self[position..-1]
+        end
+        
+        # Returns the beginning of the array up to the +position+.
+        #
+        # Examples: 
+        #   %w( a b c d ).to(0)  # => %w( a )
+        #   %w( a b c d ).to(2)  # => %w( a b c )
+        #   %w( a b c d ).to(10) # => %w( a b c d )
+        def to(position)
+          self[0..position]
+        end
+      end
+    end
+  end
+end
diff --git a/activesupport/test/core_ext/array_ext_test.rb b/activesupport/test/core_ext/array_ext_test.rb
index a5bae8c900..ade2e95c1b 100644
--- a/activesupport/test/core_ext/array_ext_test.rb
+++ b/activesupport/test/core_ext/array_ext_test.rb
@@ -1,6 +1,20 @@
 require File.dirname(__FILE__) + '/../abstract_unit'
 require 'bigdecimal'
 
+class ArrayExtAccessTests < Test::Unit::TestCase
+  def test_from
+    assert_equal %w( a b c d ), %w( a b c d ).from(0)
+    assert_equal %w( c d ), %w( a b c d ).from(2)
+    assert_nil %w( a b c d ).from(10)
+  end
+
+  def test_to
+    assert_equal %w( a ), %w( a b c d ).to(0)
+    assert_equal %w( a b c ), %w( a b c d ).to(2)
+    assert_equal %w( a b c d ), %w( a b c d ).to(10)
+  end
+end
+
 class ArrayExtToParamTests < Test::Unit::TestCase
   def test_string_array
     assert_equal '', %w().to_param