Adding Hash#compact and Hash#compact! methods

  * Adding Hash#compact and Hash#compact! methods
  * Using Ruby 1.9 syntax on documentation
  * Updating guides for `Hash#compact` and `Hash#compact!` methods
  * Updating CHANGELOG for ActiveSupport
  * Removing unecessary protected method and lambda for `Hash#compact` implementations
  * Performing `Hash#compact` implementation - https://gist.github.com/tinogomes/8332883
  * fixing order position
  * Fixing typo

1 files changed, 20 insertions, 0 deletions

diff --git a/activesupport/lib/active_support/core_ext/hash/compact.rb b/activesupport/lib/active_support/core_ext/hash/compact.rb
new file mode 100644
index 0000000000..6566215a4d
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/hash/compact.rb
@@ -0,0 +1,20 @@
+class Hash
+  # Returns a hash with non +nil+ values.
+  # 
+  #   hash = { a: true, b: false, c: nil}
+  #   hash.compact # => { a: true, b: false}
+  #   hash # => { a: true, b: false, c: nil}
+  #   { c: nil }.compact # => {}
+  def compact
+    self.select { |_, value| !value.nil? }
+  end
+  
+  # Replaces current hash with non +nil+ values.
+  # 
+  #   hash = { a: true, b: false, c: nil}
+  #   hash.compact! # => { a: true, b: false}
+  #   hash # => { a: true, b: false}
+  def compact!
+    self.reject! { |_, value| value.nil? }
+  end
+end