Yo dawg... I heard you like recursion

lib/ar_outer_join/join.rb

@@ -7,8 +7,15 @@ def initialize(klass)
     end
 
     def generate(*args)
-      args.compact.map do |arg|
-        JoinBuilder.new(klass.reflect_on_association(arg)).build
+      args.flatten.compact.map do |arg|
+        if arg.is_a?(Hash)
+          arg.map do |key, value|
+            association = klass.reflect_on_association(key)
+            generate(key) + Join.new(association.klass).generate(value)
+          end
+        else
+          JoinBuilder.new(klass.reflect_on_association(arg)).build
+        end
       end
     end
 

spec/outer_join_spec.rb

@@ -20,10 +20,13 @@ class Image < ActiveRecord::Base
   belongs_to :product
 end
 
+class Discount < ActiveRecord::Base
+  belongs_to :line_item
+end
+
 class Basket < ActiveRecord::Base; end
 class Category < ActiveRecord::Base; end
 class Site < ActiveRecord::Base; end
-class Discount < ActiveRecord::Base; end
 class Tag < ActiveRecord::Base; end
 
 describe ActiveRecord::Base do
@@ -116,5 +119,43 @@ class Tag < ActiveRecord::Base; end
         query.all.should =~ [product1, product3]
       end
     end
+
+    context "with nested associations" do
+      it "allows hashes" do
+        product1 = Product.create!
+        product2 = Product.create!
+        product3 = Product.create! :published => true
+        product4 = Product.create!
+
+        basket1 = Basket.create! :purchased => true
+        basket2 = Basket.create! :purchased => false
+
+        LineItem.create! :product => product1, :basket => basket1
+        LineItem.create! :product => product2, :basket => basket2
+        LineItem.create! :product => product3
+
+        query = Product.outer_join(:line_items => :basket).where("baskets.purchased = ? OR products.published = ?", true, true)
+        query.all.should =~ [product1, product3]
+      end
+
+      it "allows hashes with arrays" do
+        product1 = Product.create!
+        product2 = Product.create!
+        product3 = Product.create! :published => true
+        product4 = Product.create!
+
+        basket1 = Basket.create! :purchased => true
+        basket2 = Basket.create! :purchased => false
+
+        line_item1 = LineItem.create! :product => product1, :basket => basket1
+        line_item2 = LineItem.create! :product => product2, :basket => basket2
+        line_item3 = LineItem.create! :product => product4
+
+        Discount.create! :line_item => line_item3, :percentage => 80
+
+        query = Product.outer_join(:line_items => [:basket, :discounts]).where("baskets.purchased = ? OR products.published = ? OR discounts.percentage > ?", true, true, 50)
+        query.all.should =~ [product1, product3, product4]
+      end
+    end
   end
 end

spec/spec_helper.rb

@@ -29,7 +29,10 @@
   t.string :name
 end
 
-ActiveRecord::Base.connection.create_table :discounts
+ActiveRecord::Base.connection.create_table :discounts do |t|
+  t.integer :percentage, :default => 0, :null => false
+  t.integer :line_item_id
+end
 
 ActiveRecord::Base.connection.create_table :tags do |t|
   t.string :name