take advantage of inheritence for easier codes

3 files changed, 20 insertions, 18 deletions

diff --git a/lib/arel/algebra/relations/writes.rb b/lib/arel/algebra/relations/writes.rb
index d344987915..17da2b172b 100644
--- a/lib/arel/algebra/relations/writes.rb
+++ b/lib/arel/algebra/relations/writes.rb
@@ -1,33 +1,35 @@
 module Arel
-  class Deletion < Compound
-    attributes :relation
-    deriving :initialize, :==
+  class Action < Compound
+    def == other
+      super || self.class === other && @relation == other.relation
+    end
+  end
 
+  class Deletion < Action
     def call
       engine.delete(self)
     end
   end
 
-  class Insert < Compound
-    attributes :relation, :record
-    deriving :==
+  class Insert < Action
+    attr_reader :record
 
     def initialize(relation, record)
-      @relation, @record = relation, record.bind(relation)
+      super(relation)
+      @record = record.bind(relation)
     end
 
     def call
       engine.create(self)
     end
-  end
 
-  class Update < Compound
-    attributes :relation, :assignments
-    deriving :==
-
-    def initialize(relation, assignments)
-      @relation, @assignments = relation, assignments.bind(relation)
+    def == other
+      super && @record == other.record
     end
+  end
+
+  class Update < Insert
+    alias :assignments :record
 
     def call
       engine.update(self)
diff --git a/lib/arel/engines/memory/relations/writes.rb b/lib/arel/engines/memory/relations/writes.rb
index 12c4f36c0d..39c1170ddc 100644
--- a/lib/arel/engines/memory/relations/writes.rb
+++ b/lib/arel/engines/memory/relations/writes.rb
@@ -1,5 +1,5 @@
 module Arel
-  class Insert < Compound
+  class Insert < Action
     def eval
       unoperated_rows + [Row.new(self, record.values.collect(&:value))]
     end
diff --git a/lib/arel/engines/sql/relations/writes.rb b/lib/arel/engines/sql/relations/writes.rb
index 4ed817f85d..50a2ce2e99 100644
--- a/lib/arel/engines/sql/relations/writes.rb
+++ b/lib/arel/engines/sql/relations/writes.rb
@@ -1,17 +1,17 @@
 module Arel
-  class Deletion < Compound
+  class Deletion < Action
     def to_sql
       compiler.delete_sql
     end
   end
 
-  class Insert < Compound
+  class Insert < Action
     def to_sql(include_returning = true)
       compiler.insert_sql(include_returning)
     end
   end
 
-  class Update < Compound
+  class Update < Insert
     def to_sql
       compiler.update_sql
     end