Permalink
Browse files

Added availability of class inheritable attributes to the masses #477

…[bitsweat]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@412 5ecf4fe2-1ee6-0310-87b1-e25e094e27de
  • Loading branch information...
1 parent f73ecc8 commit 38e695037cb736196af05e0f4587742915ceee89 @dhh dhh committed Jan 15, 2005
Showing with 122 additions and 33 deletions.
  1. +18 −0 activesupport/CHANGELOG
  2. +104 −33 activesupport/lib/class_inheritable_attributes.rb
View
@@ -1,3 +1,21 @@
+* Added availability of class inheritable attributes to the masses #477 [bitsweat]
+
+ class Foo
+ class_inheritable_reader :read_me
+ class_inheritable_writer :write_me
+ class_inheritable_accessor :read_and_write_me
+ class_inheritable_array :read_and_concat_me
+ class_inheritable_hash :read_and_update_me
+ end
+
+ # Bar gets a clone of (not a reference to) Foo's attributes.
+ class Bar < Foo
+ end
+
+ Bar.read_and_write_me == Foo.read_and_write_me
+ Bar.read_and_write_me = 'bar'
+ Bar.read_and_write_me != Foo.read_and_write_me
+
* Added Inflections as an extension on String, so Inflector.pluralize(Inflector.classify(name)) becomes name.classify.pluralize #476 [bitsweat]
* Added Byte operations to Numeric, so 5.5.megabytes + 200.kilobytes #461 [Marcel Molina]
@@ -1,46 +1,117 @@
+# Retain for backward compatibility. Methods are now included in Class.
+module ClassInheritableAttributes # :nodoc:
+end
+
# Allows attributes to be shared within an inheritance hierarchy, but where each descendant gets a copy of
# their parents' attributes, instead of just a pointer to the same. This means that the child can add elements
# to, for example, an array without those additions being shared with either their parent, siblings, or
# children, which is unlike the regular class-level attributes that are shared across the entire hierarchy.
-module ClassInheritableAttributes # :nodoc:
- def self.append_features(base)
- super
- base.extend(ClassMethods)
- end
-
- module ClassMethods # :nodoc:
- @@classes ||= {}
-
- def inheritable_attributes
- @@classes[self] ||= {}
- end
-
- def write_inheritable_attribute(key, value)
- inheritable_attributes[key] = value
- end
-
- def write_inheritable_array(key, elements)
- write_inheritable_attribute(key, []) if read_inheritable_attribute(key).nil?
- write_inheritable_attribute(key, read_inheritable_attribute(key) + elements)
+class Class # :nodoc:
+ def class_inheritable_reader(*syms)
+ syms.each do |sym|
+ class_eval <<-EOS
+ def self.#{sym}
+ read_inheritable_attribute(:#{sym})
+ end
+
+ def #{sym}
+ self.class.#{sym}
+ end
+ EOS
end
+ end
- def write_inheritable_hash(key, hash)
- write_inheritable_attribute(key, {}) if read_inheritable_attribute(key).nil?
- write_inheritable_attribute(key, read_inheritable_attribute(key).merge(hash))
+ def class_inheritable_writer(*syms)
+ syms.each do |sym|
+ class_eval <<-EOS
+ def self.#{sym}=(obj)
+ write_inheritable_attribute(:#{sym}, obj)
+ end
+
+ def #{sym}=(obj)
+ self.class.#{sym} = obj
+ end
+ EOS
end
+ end
+
+ def class_inheritable_array_writer(*syms)
+ syms.each do |sym|
+ class_eval <<-EOS
+ def self.#{sym}=(obj)
+ write_inheritable_array(:#{sym}, obj)
+ end
- def read_inheritable_attribute(key)
- inheritable_attributes[key]
+ def #{sym}=(obj)
+ self.class.#{sym} = obj
+ end
+ EOS
end
-
- def reset_inheritable_attributes
- inheritable_attributes.clear
+ end
+
+ def class_inheritable_hash_writer(*syms)
+ syms.each do |sym|
+ class_eval <<-EOS
+ def self.#{sym}=(obj)
+ write_inheritable_hash(:#{sym}, obj)
+ end
+
+ def #{sym}=(obj)
+ self.class.#{sym} = obj
+ end
+ EOS
end
+ end
+
+ def class_inheritable_accessor(*syms)
+ class_inheritable_reader(*syms)
+ class_inheritable_writer(*syms)
+ end
- private
- def inherited(child)
- @@classes[child] = inheritable_attributes.dup
- end
-
+ def class_inheritable_array(*syms)
+ class_inheritable_reader(*syms)
+ class_inheritable_array_writer(*syms)
end
+
+ def class_inheritable_hash(*syms)
+ class_inheritable_reader(*syms)
+ class_inheritable_hash_writer(*syms)
+ end
+
+ def inheritable_attributes
+ @inheritable_attributes ||= {}
+ end
+
+ def write_inheritable_attribute(key, value)
+ inheritable_attributes[key] = value
+ end
+
+ def write_inheritable_array(key, elements)
+ write_inheritable_attribute(key, []) if read_inheritable_attribute(key).nil?
+ write_inheritable_attribute(key, read_inheritable_attribute(key) + elements)
+ end
+
+ def write_inheritable_hash(key, hash)
+ write_inheritable_attribute(key, {}) if read_inheritable_attribute(key).nil?
+ write_inheritable_attribute(key, read_inheritable_attribute(key).merge(hash))
+ end
+
+ def read_inheritable_attribute(key)
+ inheritable_attributes[key]
+ end
+
+ def reset_inheritable_attributes
+ inheritable_attributes.clear
+ end
+
+ private
+ def inherited_with_inheritable_attributes(child)
+ inherited_without_inheritable_attributes(child) if respond_to?(:inherited_without_inheritable_attributes)
+ child.instance_variable_set('@inheritable_attributes', inheritable_attributes.dup)
+ end
+
+ if respond_to?(:inherited)
+ alias_method :inherited_without_inheritable_attributes, :inherited
+ end
+ alias_method :inherited, :inherited_with_inheritable_attributes
end

0 comments on commit 38e6950

Please sign in to comment.