attr_internal to support namespacing and deprecation

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4692 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

2 files changed, 32 insertions, 0 deletions

diff --git a/activesupport/lib/active_support/core_ext/module.rb b/activesupport/lib/active_support/core_ext/module.rb
index 45069f52af..8d48de53dd 100644
--- a/activesupport/lib/active_support/core_ext/module.rb
+++ b/activesupport/lib/active_support/core_ext/module.rb
@@ -1,5 +1,6 @@
 require File.dirname(__FILE__) + '/module/inclusion'
 require File.dirname(__FILE__) + '/module/attribute_accessors'
+require File.dirname(__FILE__) + '/module/attr_internal'
 require File.dirname(__FILE__) + '/module/delegation'
 require File.dirname(__FILE__) + '/module/introspection'
 require File.dirname(__FILE__) + '/module/loading'
diff --git a/activesupport/lib/active_support/core_ext/module/attr_internal.rb b/activesupport/lib/active_support/core_ext/module/attr_internal.rb
new file mode 100644
index 0000000000..c793da7159
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/module/attr_internal.rb
@@ -0,0 +1,31 @@
+class Module
+  # Declare an attribute reader backed by an internally-named instance variable.
+  def attr_internal_reader(*attrs)
+    attrs.each do |attr|
+      module_eval "def #{attr}() #{attr_internal_ivar_name(attr)} end"
+    end
+  end
+
+  # Declare an attribute writer backed by an internally-named instance variable.
+  def attr_internal_writer(*attrs)
+    attrs.each do |attr|
+      module_eval "def #{attr}=(v) #{attr_internal_ivar_name(attr)} = v end"
+    end
+  end
+
+  # Declare attributes backed by 'internal' instance variables names.
+  def attr_internal_accessor(*attrs)
+    attr_internal_reader *attrs
+    attr_internal_writer *attrs
+  end
+
+  alias_method :attr_internal, :attr_internal_accessor
+
+  private
+    mattr_accessor :attr_internal_naming_format
+    self.attr_internal_naming_format = '@_%s'
+
+    def attr_internal_ivar_name(attr)
+      attr_internal_naming_format % attr
+    end
+end