Added Module#alias_attribute [Jamis/DHH]

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

activesupport/CHANGELOG

@@ -1,5 +1,22 @@
 *SVN*
 
+* Added Module#alias_attribute [Jamis/DHH]. 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"
+
 * Deprecation: easier to work with warning behavior as procs; default behaviors for each environment so users needn't update env.rb; and testing pleasure with assert_deprecated, assert_not_deprecated. [Jeremy Kemper]
   By default, test prints to $stderr, dev logs, production ignores.
   Provide your own per-environment in e.g. config/environments/development.rb:

activesupport/lib/active_support/core_ext/date/conversions.rb

@@ -25,9 +25,11 @@ def to_date
         def to_time(form = :local)
           ::Time.send(form, year, month, day)
         end
-
-        alias :xmlschema :to_s
+
+        def xmlschema
+          to_time.xmlschema
+        end
       end
     end
   end
-end
+end

activesupport/lib/active_support/core_ext/module/aliasing.rb

@@ -27,4 +27,31 @@ def alias_method_chain(target, feature)
     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

activesupport/test/core_ext/module/attribute_aliasing_test.rb

@@ -0,0 +1,31 @@
+require File.dirname(__FILE__) + '/../../abstract_unit'
+
+module AttributeAliasing
+  class Content
+    attr_accessor :title
+
+    def title?
+      !title.nil?
+    end
+  end
+
+  class Email < Content
+    alias_attribute :subject, :title
+  end
+end
+
+class AttributeAliasingTest < Test::Unit::TestCase
+  def test_attribute_alias
+    e = AttributeAliasing::Email.new
+
+    assert !e.subject?
+
+    e.title = "Upgrade computer"
+    assert_equal "Upgrade computer", e.subject
+    assert e.subject?
+
+    e.subject = "We got a long way to go"
+    assert_equal "We got a long way to go", e.title
+    assert e.title?
+  end
+end

activesupport/test/core_ext/module_test.rb

@@ -117,7 +117,6 @@ def quux_with_baz?
 end
 
 class MethodAliasingTest < Test::Unit::TestCase
-
   def setup
     Object.const_set(:FooClassWithBarMethod, Class.new)
     FooClassWithBarMethod.send(:define_method, 'bar', Proc.new { 'bar' })