Support for modules with attributes

lib/virtus.rb

@@ -23,10 +23,17 @@ module Virtus
   # @return [undefined]
   #
   # @api private
-  def self.included(descendant)
+  def self.included(object)
     super
-    descendant.extend(ClassMethods)
-    descendant.send(:include, InstanceMethods)
+    case object
+    when Class  then object.send(:include, ClassInclusions)
+    when Module then object.extend(ModuleExtensions)
+    end
+  end
+
+  def self.extended(object)
+    object.extend(InstanceExtensions)
+    object.extend(InstanceMethods)
   end
 
   private_class_method :included
@@ -38,6 +45,10 @@ def self.included(descendant)
 require 'virtus/support/options'
 require 'virtus/support/equalizer'
 
+require 'virtus/instance_extensions'
+require 'virtus/class_inclusions'
+require 'virtus/module_extensions'
+
 require 'virtus/attributes_accessor'
 require 'virtus/class_methods'
 require 'virtus/instance_methods'

lib/virtus/class_inclusions.rb

@@ -0,0 +1,20 @@
+module Virtus
+  module ClassInclusions
+
+    def self.included(descendant)
+      super
+      descendant.extend(ClassMethods)
+      descendant.extend(InstanceExtensions::AllowedWriterMethods)
+      descendant.send(:include, InstanceMethods)
+    end
+
+    def _attributes
+      self.class.attributes
+    end
+
+    def allowed_writer_methods
+      self.class.allowed_writer_methods
+    end
+
+  end # module ClassInclusions
+end # module Virtus

lib/virtus/class_methods.rb

@@ -2,8 +2,7 @@ module Virtus
 
   # Class methods that are added when you include Virtus
   module ClassMethods
-    WRITER_METHOD_REGEXP   = /=\z/.freeze
-    INVALID_WRITER_METHODS = %w[ == != === []= attributes= ].to_set.freeze
+    include InstanceExtensions
 
     # Hook called when module is extended
     #
@@ -22,39 +21,6 @@ def self.extended(descendant)
 
     private_class_method :extended
 
-    # Defines an attribute on an object's class
-    #
-    # @example
-    #    class Book
-    #      include Virtus
-    #
-    #      attribute :title,        String
-    #      attribute :author,       String
-    #      attribute :published_at, DateTime
-    #      attribute :page_count,   Integer
-    #    end
-    #
-    # @param [Symbol] name
-    #   the name of an attribute
-    #
-    # @param [Class] type
-    #   the type class of an attribute
-    #
-    # @param [#to_hash] options
-    #   the extra options hash
-    #
-    # @return [self]
-    #
-    # @see Attribute.build
-    #
-    # @api public
-    def attribute(*args)
-      attribute = Attribute.build(*args)
-      attribute.define_accessor_methods(virtus_attributes_accessor_module)
-      virtus_add_attribute(attribute)
-      self
-    end
-
     # Returns all the attributes defined on a Class
     #
     # @example
@@ -79,21 +45,7 @@ def attributes
       parent      = superclass.public_send(method) if superclass.respond_to?(method)
       @attributes = AttributeSet.new(parent)
     end
-
-    # The list of writer methods that can be mass-assigned to in #attributes=
-    #
-    # @return [Set]
-    #
-    # @api private
-    def allowed_writer_methods
-      @allowed_writer_methods ||=
-        begin
-          allowed_writer_methods  = public_instance_methods.map(&:to_s)
-          allowed_writer_methods  = allowed_writer_methods.grep(WRITER_METHOD_REGEXP).to_set
-          allowed_writer_methods -= INVALID_WRITER_METHODS
-          allowed_writer_methods.freeze
-        end
-    end
+    alias _attributes attributes
 
   protected
 
@@ -104,7 +56,7 @@ def allowed_writer_methods
     # @api private
     def virtus_setup_attributes_accessor_module
       @virtus_attributes_accessor_module = AttributesAccessor.new(inspect)
-      include virtus_attributes_accessor_module
+      include @virtus_attributes_accessor_module
       self
     end
 
@@ -128,13 +80,6 @@ def inherited(descendant)
       descendant.virtus_setup_attributes_accessor_module
     end
 
-    # Holds the anonymous module which hosts this class's Attribute accessors
-    #
-    # @return [Module]
-    #
-    # @api private
-    attr_reader :virtus_attributes_accessor_module
-
     # Hooks into const missing process to determine types of attributes
     #
     # @param [String] name
@@ -154,9 +99,13 @@ def const_missing(name)
     #
     # @api private
     def virtus_add_attribute(attribute)
-      attributes << attribute
+      super
       descendants.each { |descendant| descendant.attributes.reset }
     end
 
+    def public_method_list
+      public_instance_methods
+    end
+
   end # module ClassMethods
 end # module Virtus

lib/virtus/instance_extensions.rb

@@ -0,0 +1,75 @@
+module Virtus
+
+  # Instance-level extensions
+  module InstanceExtensions
+    module AllowedWriterMethods
+      WRITER_METHOD_REGEXP   = /=\z/.freeze
+      INVALID_WRITER_METHODS = %w[ == != === []= attributes= ].to_set.freeze
+
+      # The list of writer methods that can be mass-assigned to in #attributes=
+      #
+      # @return [Set]
+      #
+      # @api private
+      def allowed_writer_methods
+        @allowed_writer_methods ||=
+          begin
+            allowed_writer_methods  = public_method_list.map(&:to_s)
+            allowed_writer_methods  = allowed_writer_methods.grep(WRITER_METHOD_REGEXP).to_set
+            allowed_writer_methods -= INVALID_WRITER_METHODS
+            allowed_writer_methods.freeze
+          end
+      end
+    end
+
+    def self.extended(object)
+      object.extend(AllowedWriterMethods)
+      object.extend(InstanceMethods)
+      object.instance_eval do
+        @virtus_attributes_accessor_module = AttributesAccessor.new(object.class.inspect)
+        extend @virtus_attributes_accessor_module
+      end
+    end
+
+    # Defines an attribute on an object's class
+    #
+    # @example
+    #    class Book
+    #      include Virtus
+    #
+    #      attribute :title,        String
+    #      attribute :author,       String
+    #      attribute :published_at, DateTime
+    #      attribute :page_count,   Integer
+    #    end
+    #
+    # @param [Symbol] name
+    #   the name of an attribute
+    #
+    # @param [Class] type
+    #   the type class of an attribute
+    #
+    # @param [#to_hash] options
+    #   the extra options hash
+    #
+    # @return [self]
+    #
+    # @see Attribute.build
+    #
+    # @api public
+    def attribute(*args)
+      attribute = Attribute.build(*args)
+      attribute.define_accessor_methods(@virtus_attributes_accessor_module)
+      virtus_add_attribute(attribute)
+      self
+    end
+
+    def _attributes
+      @_attributes ||= AttributeSet.new
+    end
+
+    def virtus_add_attribute(attribute)
+      _attributes << attribute
+    end
+  end # module InstanceExtensions
+end # module Virtus

lib/virtus/instance_methods.rb

@@ -140,7 +140,7 @@ def to_hash
     #
     # @api private
     def get_attributes
-      self.class.attributes.each_with_object({}) do |attribute, attributes|
+      _attributes.each_with_object({}) do |attribute, attributes|
         name = attribute.name
         attributes[name] = get_attribute(name) if yield(attribute)
       end
@@ -155,7 +155,7 @@ def get_attributes
     # @api private
     def set_attributes(attributes)
       ::Hash.try_convert(attributes).each do |name, value|
-        set_attribute(name, value) if self.class.allowed_writer_methods.include?("#{name}=")
+        set_attribute(name, value) if allowed_writer_methods.include?("#{name}=")
       end
     end
 
@@ -181,5 +181,10 @@ def set_attribute(name, value)
       __send__("#{name}=", value)
     end
 
+    # @api private
+    def public_method_list
+      public_methods
+    end
+
   end # module InstanceMethods
 end # module Virtus

lib/virtus/module_extensions.rb

@@ -0,0 +1,34 @@
+module Virtus
+
+  # Virtus module class that can define attributes for later inclusion
+  #
+  module ModuleExtensions
+
+    def extended(object)
+      object.extend(Virtus)
+      define_attributes(object)
+    end
+
+    def included(object)
+      object.send(:include, ClassInclusions)
+      define_attributes(object)
+    end
+
+    def attribute(*args)
+      attribute_definitions << args
+    end
+
+  private
+
+    def attribute_definitions
+      @_attribute_definitions ||= []
+    end
+
+    def define_attributes(object)
+      attribute_definitions.each do |attribute_args|
+        object.attribute(*attribute_args)
+      end
+    end
+
+  end # class Module
+end # module Virtus

lib/virtus/value_object.rb

@@ -63,6 +63,7 @@ def clone
         self
       end
       alias dup clone
+
     end
 
     module ClassMethods
@@ -122,7 +123,7 @@ def allowed_writer_methods
         @allowed_writer_methods ||=
           begin
             allowed_writer_methods = super
-            allowed_writer_methods += attributes.map{|attr| "#{attr.name}="}
+            allowed_writer_methods += _attributes.map{|attr| "#{attr.name}="}
             allowed_writer_methods.to_set.freeze
           end
       end

spec/integration/extending_objects_spec.rb

@@ -0,0 +1,35 @@
+require 'spec_helper'
+
+describe 'I can extend objects' do
+  before do
+    module Examples
+      class User; end
+
+      class Admin; end
+    end
+  end
+
+  specify 'defining attributes on an object' do
+    attributes = { :name => 'John', :age => 29 }
+
+    admin = Examples::Admin.new
+    admin.extend(Virtus)
+
+    admin.attribute :name, String
+    admin.attribute :age,  Integer
+
+    admin.name = 'John'
+    admin.age  = 29
+
+    admin.name.should eql('John')
+    admin.age.should eql(29)
+
+    admin.attributes.should eql(attributes)
+
+    new_attributes   = { :name => 'Jane', :age => 28 }
+    admin.attributes = new_attributes
+
+    admin.name.should eql('Jane')
+    admin.age.should eql(28)
+  end
+end