Adding concat and difference to criteria

lib/mongoid/criteria.rb

@@ -21,6 +21,18 @@ class Criteria
 
     attr_reader :klass, :options, :selector
 
+    # Concatinate the criteria with another enumerable. If the other is a
+    # +Criteria+ then it needs to get the collection from it.
+    def +(other)
+      collect + (other.is_a?(Criteria) ? other.collect : other)
+    end
+
+    # Returns the difference between the criteria and another enumerable. If
+    # the other is a +Criteria+ then it needs to get the collection from it.
+    def -(other)
+      collect - (other.is_a?(Criteria) ? other.collect : other)
+    end
+
     # Returns true if the supplied +Enumerable+ or +Criteria+ is equal to the results
     # of this +Criteria+ or the criteria itself.
     #
@@ -499,6 +511,9 @@ def sum(field)
       grouped(:sum, field.to_s, SUM_REDUCE)
     end
 
+    alias :to_a :collect
+    alias :to_ary :collect
+
     # Translate the supplied arguments into a +Criteria+ object.
     #
     # If the passed in args is a single +String+, then it will

lib/mongoid/extensions/array/accessors.rb

@@ -9,6 +9,8 @@ def update(attributes)
           delete_if { |e| attributes["_id"] && (e["_id"] == attributes["_id"]) }
           self.<< attributes
         end
+
+        alias :merge! :update
       end
     end
   end

lib/mongoid/extensions/hash/accessors.rb

@@ -21,7 +21,7 @@ def remove(key, attrs)
         def insert(key, attrs)
           elements = self[key]
           if elements
-            elements.update(attrs)
+            elements.merge!(attrs)
           else
             self[key] = key.singular? ? attrs : [attrs]
           end

spec/integration/mongoid/associations_spec.rb

@@ -113,6 +113,24 @@
 
       end
 
+      context "when a has-one to has-many" do
+
+        before do
+          @person = Person.new(:title => "Sir")
+          @name = Name.new(:first_name => "Syd")
+          @person.name = @name
+          @person.save
+        end
+
+        it "persists all the associations properly" do
+          from_db = Person.find(@person.id)
+          translation = Translation.new(:language => "fr")
+          from_db.name.translations << translation
+          from_db.attributes[:name][:translations].should_not be_nil
+        end
+
+      end
+
       context "when a has-many to has-many" do
 
         before do

spec/spec_helper.rb

@@ -173,13 +173,20 @@ class Name
   field :last_name
   field :parent_title
   key :first_name, :last_name
+  has_many :translations
   belongs_to :person, :inverse_of => :name
 
   def set_parent=(set = false)
     self.parent_title = person.title if set
   end
 end
 
+class Translation
+  include Mongoid::Document
+  field :language
+  belongs_to :name, :inverse_of => :translations
+end
+
 class Comment
   include Mongoid::Document
   include Mongoid::Versioning

spec/unit/mongoid/criteria_spec.rb

@@ -7,6 +7,111 @@
     @canvas_criteria = Mongoid::Criteria.new(Canvas)
   end
 
+  describe "#+" do
+
+    before do
+      @sir = Person.new(:title => "Sir")
+      @madam = Person.new(:title => "Madam")
+      @canvas = Canvas.new
+    end
+
+    context "when the criteria has not been executed" do
+
+      before do
+        @collection = mock
+        @cursor = stub(:count => 1, :collect => [ @sir, @madam ])
+        Person.expects(:collection).returns(@collection)
+        @collection.expects(:find).returns(@cursor)
+      end
+
+      it "executes the criteria and concats the results" do
+        results = @criteria + [ @canvas ]
+        results.should == [ @sir, @madam, @canvas ]
+      end
+
+    end
+
+    context "when the criteria has been executed" do
+
+      before do
+        @criteria.instance_variable_set(:@collection, [ @sir, @madam ])
+      end
+
+      it "concats the results" do
+        results = @criteria + [ @canvas ]
+        results.should == [ @sir, @madam, @canvas ]
+      end
+
+    end
+
+    context "when the other is a criteria" do
+
+      before do
+        @criteria.instance_variable_set(:@collection, [ @sir, @madam ])
+        @canvas_criteria.instance_variable_set(:@collection, [ @canvas ])
+      end
+
+      it "concats the results" do
+        results = @criteria + @canvas_criteria
+        results.should == [ @sir, @madam, @canvas ]
+      end
+
+    end
+
+  end
+
+  describe "#-" do
+
+    before do
+      @sir = Person.new(:title => "Sir")
+      @madam = Person.new(:title => "Madam")
+    end
+
+    context "when the criteria has not been executed" do
+
+      before do
+        @collection = mock
+        @cursor = stub(:count => 1, :collect => [ @sir, @sir, @madam ])
+        Person.expects(:collection).returns(@collection)
+        @collection.expects(:find).returns(@cursor)
+      end
+
+      it "executes the criteria and returns the difference" do
+        results = @criteria - [ @sir ]
+        results.should == [ @madam ]
+      end
+
+    end
+
+    context "when the criteria has been executed" do
+
+      before do
+        @criteria.instance_variable_set(:@collection, [@sir, @sir, @madam])
+      end
+
+      it "returns the difference" do
+        results = @criteria - [ @sir ]
+        results.should == [ @madam ]
+      end
+
+    end
+
+    context "when the other is a criteria" do
+
+      before do
+        @criteria.instance_variable_set(:@collection, [@sir, @sir, @madam])
+        @canvas_criteria.instance_variable_set(:@collection, [@sir])
+      end
+
+      it "returns the difference" do
+        results = @criteria - @canvas_criteria
+        results.should == [ @madam ]
+      end
+
+    end
+
+  end
+
   describe "#[]" do
 
     before do