Added ActiveAttr::BlockInitializations, closes #33

CHANGELOG.md

@@ -1,5 +1,7 @@
 # ActiveAttr 0.3.0 (unreleased) #
 
+* Added BlockInitialization
+
 # ActiveAttr 0.2.2 (November 2, 2011) #
 
 * Fixed all instances of modules' #initialize not invoking its superclass

README.md

@@ -24,10 +24,10 @@ the attributes of your model.
       attribute :last_name
     end
 
-    p = Person.new
-    p.first_name = "Chris"
-    p.last_name = "Griego"
-    p.attributes #=> {"first_name"=>"Chris", "last_name"=>"Griego"}
+    person = Person.new
+    person.first_name = "Chris"
+    person.last_name = "Griego"
+    person.attributes #=> {"first_name"=>"Chris", "last_name"=>"Griego"}
 
 ### BasicModel ###
 
@@ -39,9 +39,27 @@ required for your model to meet the ActiveModel API requirements.
     end
 
     Person.model_name.plural #=> "people"
-    p = Person.new
-    p.valid? #=> true
-    p.errors.full_messages #=> []
+    person = Person.new
+    person.valid? #=> true
+    person.errors.full_messages #=> []
+
+### BlockInitialization ###
+
+Including the BlockInitialization module into your class will yield the model
+instance to a block passed to when creating a new instance.
+
+    class Person
+      include ActiveAttr::BlockInitialization
+      attr_accessor :first_name, :last_name
+    end
+
+    person = Person.new do |p|
+      p.first_name = "Chris"
+      p.last_name = "Griego"
+    end
+
+    person.first_name #=> "Chris"
+    person.last_name #=> "Griego"
 
 ### MassAssignment ###
 
@@ -56,10 +74,10 @@ attribute.
       attr_accessor :first_name, :last_name
     end
 
-    p = Person.new(:first_name => "Chris")
-    p.attributes = { :last_name => "Griego" }
-    p.first_name #=> "Chris"
-    p.last_name #=> "Griego"
+    person = Person.new(:first_name => "Chris")
+    person.attributes = { :last_name => "Griego" }
+    person.first_name #=> "Chris"
+    person.last_name #=> "Griego"
 
 ## RSpec Integration ##
 

lib/active_attr/block_initialization.rb

@@ -0,0 +1,37 @@
+require "active_attr/chainable_initialization"
+require "active_support/concern"
+
+module ActiveAttr
+  # BlockInitialization allows you to build an instance in a block
+  #
+  # Including the BlockInitialization module into your class will yield the
+  # model instance to a block passed to when creating a new instance.
+  #
+  # @example Usage
+  #   class Person
+  #     include ActiveAttr::BlockInitialization
+  #   end
+  #
+  # @since 0.3.0
+  module BlockInitialization
+    extend ActiveSupport::Concern
+    include ChainableInitialization
+
+    # Initialize a model and build via a block
+    #
+    # @example
+    #   person = Person.new do |p|
+    #     p.first_name = "Chris"
+    #     p.last_name = "Griego"
+    #   end
+    #
+    #   person.first_name #=> "Chris"
+    #   person.last_name #=> "Griego"
+    #
+    # @since 0.3.0
+    def initialize(*)
+      super
+      yield self if block_given?
+    end
+  end
+end

spec/unit/active_attr/block_initialization_spec.rb

@@ -0,0 +1,39 @@
+require "spec_helper"
+require "active_attr/block_initialization"
+
+module ActiveAttr
+  describe BlockInitialization do
+    subject { model_class.new("arg") {} }
+
+    let :model_class do
+      Class.new do
+        include InitializationVerifier
+        include BlockInitialization
+
+        def initialize(arg)
+          super
+        end
+      end
+    end
+
+    describe "#initialize" do
+      it "invokes the superclass initializer" do
+        should be_initialized
+      end
+
+      it "doesn't raise when not passed a block" do
+        expect { model_class.new("arg") }.not_to raise_error
+      end
+
+      it "yields the new instance" do
+        yielded_instance = nil
+
+        returned_instance = model_class.new("arg") do |yielded|
+          yielded_instance = yielded
+        end
+
+        returned_instance.should equal yielded_instance
+      end
+    end
+  end
+end