Explicit mapping for enum

activerecord/lib/active_record/enum.rb

@@ -3,6 +3,9 @@ module ActiveRecord
   #
   #   class Conversation < ActiveRecord::Base
   #     enum status: [:active, :archived]
+  #
+  #     # same but with explicit mapping
+  #     enum status: {active: 0, archived: 1}
   #   end
   #
   #   Conversation::STATUS # => { active: 0, archived: 1 }
@@ -41,7 +44,8 @@ module ActiveRecord
         # def direction() DIRECTION.key self[:direction] end
         class_eval "def #{name}() #{const_name}.key self[:#{name}] end"
 
-        values.each_with_index do |value, i|
+        pairs = values.respond_to?(:each_pair) ? values.each_pair : values.each_with_index
+        pairs.each do |value, i|
           # DIRECTION[:incoming] = 0
           const_get(const_name)[value] = i
 

activerecord/test/cases/enum_test.rb

@@ -12,14 +12,18 @@ class StoreTest < ActiveRecord::TestCase
     assert @book.proposed?
     assert_not @book.written?
     assert_not @book.published?
+
+    assert @book.unread?
   end
 
   test "query state with symbol" do
     assert_equal :proposed, @book.status
+    assert_equal :unread, @book.read_status
   end
 
   test "find via scope" do
     assert_equal @book, Book.proposed.first
+    assert_equal @book, Book.unread.first
   end
 
   test "update by declaration" do
@@ -36,5 +40,9 @@ class StoreTest < ActiveRecord::TestCase
     assert_equal 0, Book::STATUS[:proposed]
     assert_equal 1, Book::STATUS[:written]
     assert_equal 2, Book::STATUS[:published]
+
+    assert_equal 0, Book::READ_STATUS[:unread]
+    assert_equal 2, Book::READ_STATUS[:reading]
+    assert_equal 3, Book::READ_STATUS[:read]
   end
 end

activerecord/test/models/book.rb

@@ -8,4 +8,5 @@ class Book < ActiveRecord::Base
   has_many :subscribers, through: :subscriptions
 
   enum status: [:proposed, :written, :published]
+  enum read_status: {unread: 0, reading: 2, read: 3}
 end

activerecord/test/schema/schema.rb

@@ -95,6 +95,7 @@ ActiveRecord::Schema.define do
     t.integer :author_id
     t.column :name, :string
     t.column :status, :integer, default: 0
+    t.column :read_status, :integer, default: 0
   end
 
   create_table :booleans, :force => true do |t|