prodis · October 25, 2017 21:33 · Oct 25, 2017 · Oct 25, 2017 · Oct 25, 2017
diff --git a/init_attributes.rb b/init_attributes.rb
@@ -59,6 +59,7 @@ def do_something
 # instance variables: @accessor_attributes  @reader_attributes
 
 akira = Akira.new(one: 1, two: 2)
+# => #<Akira:0x007ff1da152e48 @one=1, @two=2>
 
 ls akira
 # Akira#methods: do_something  one  two  two=

diff --git a/init_attributes.rb b/init_attributes.rb
@@ -0,0 +1,68 @@
+module InitAttributes
+  def self.included(base)
+    base.send(:include, InstanceMethods)
+    base.extend(ClassMethods)
+  end
+
+  module InstanceMethods
+    def initialize(attributes)
+      init_instance_variables(self.class.accessor_attributes, attributes)
+      init_instance_variables(self.class.reader_attributes,   attributes)
+    end
+
+    private
+
+    def init_instance_variables(required_attributes, given_attributes)
+      required_attributes.each do |attr|
+        instance_variable_set("@#{attr}", given_attributes.fetch(attr))
+      end
+    end
+  end
+
+  module ClassMethods
+    def accessor_attributes
+      @accessor_attributes ||= []
+    end
+
+    def reader_attributes
+      @reader_attributes ||= []
+    end
+
+    private
+
+    def init_attr_accessor(*attributes)
+      attr_accessor(*attributes)
+      @accessor_attributes = attributes
+    end
+
+    def init_attr_reader(*attributes)
+      attr_reader(*attributes)
+      @reader_attributes = attributes
+    end
+  end
+end
+
+class Akira
+  include InitAttributes
+
+  init_attr_reader   :one
+  init_attr_accessor :two
+
+  def do_something
+    puts 'Doing something...'
+  end
+end
+
+ls Akira
+# InitAttributes::ClassMethods#methods: accessor_attributes  reader_attributes
+# Akira#methods: do_something  one  two  two=
+# instance variables: @accessor_attributes  @reader_attributes
+
+akira = Akira.new(one: 1, two: 2)
+
+ls akira
+# Akira#methods: do_something  one  two  two=
+# instance variables: @one  @two
+
+Akira.new(one: 1)
+# => KeyError: key not found: :two