Added Module#alias_attribute [Jamis/DHH]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4653 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

1 files changed, 27 insertions, 0 deletions

diff --git a/activesupport/lib/active_support/core_ext/module/aliasing.rb b/activesupport/lib/active_support/core_ext/module/aliasing.rb
index 09209884b6..a4c7e539e3 100644
--- a/activesupport/lib/active_support/core_ext/module/aliasing.rb
+++ b/activesupport/lib/active_support/core_ext/module/aliasing.rb
@@ -27,4 +27,31 @@ class Module
     alias_method "#{aliased_target}_without_#{feature}#{punctuation}", target
     alias_method target, "#{aliased_target}_with_#{feature}#{punctuation}"
   end
+
+  # Allows you to make aliases for attributes, which includes 
+  # getter, setter, and query methods.
+  #
+  # Example:
+  #
+  #   class Content < ActiveRecord::Base
+  #     # has a title attribute
+  #   end
+  #
+  #   class Email < ActiveRecord::Base
+  #     alias_attribute :subject, :title
+  #   end
+  #
+  #   e = Email.find(1)
+  #   e.title    # => "Superstars"
+  #   e.subject  # => "Superstars"
+  #   e.subject? # => true
+  #   e.subject = "Megastars"
+  #   e.title    # => "Megastars"
+  def alias_attribute(new_name, old_name)
+    module_eval <<-STR, __FILE__, __LINE__+1
+      def #{new_name}; #{old_name}; end
+      def #{new_name}?; #{old_name}?; end
+      def #{new_name}=(v); self.#{old_name} = v; end
+    STR
+  end
 end