removed more boiler-plate

lib/arel/primitives/attribute.rb

@@ -2,7 +2,8 @@ require 'set'
 
 module Arel
   class Attribute
-    attr_reader :relation, :name, :alias, :ancestor
+    attributes :relation, :name, :alias, :ancestor
+    deriving :==
     delegate :engine, :christener, :to => :relation
 
     def initialize(relation, name, options = {})
@@ -29,26 +30,6 @@ module Arel
       formatter.attribute self
     end
 
-    def ==(other)
-      Attribute   === other           and
-      name        ==  other.name      and
-      @alias      ==  other.alias     and
-      ancestor    ==  other.ancestor  and
-      relation    ==  other.relation
-    end
-
-    def original_relation
-      @original_relation ||= original_attribute.relation
-    end
-    
-    def original_attribute
-      @original_attribute ||= history.detect { |a| !a.join? }
-    end
-    
-    def find_correlate_in(relation)
-      relation[self]
-    end
-
     module Transformations      
       def self.included(klass)
         klass.send :alias_method, :eql?, :==
@@ -85,6 +66,18 @@ module Arel
         history.last
       end
       
+      def original_relation
+        @original_relation ||= original_attribute.relation
+      end
+
+      def original_attribute
+        @original_attribute ||= history.detect { |a| !a.join? }
+      end
+
+      def find_correlate_in(relation)
+        relation[self]
+      end
+          
       def descends_from?(other)
         history.include?(other)
       end

lib/arel/primitives/expression.rb

@@ -1,6 +1,7 @@
 module Arel
   class Expression < Attribute
-    attr_reader :attribute, :function_sql
+    attributes :attribute, :function_sql, :alias, :ancestor
+    deriving :==
     delegate :relation, :to => :attribute
     alias_method :name, :alias
     
@@ -16,14 +17,6 @@ module Arel
       true
     end
     
-    def ==(other)
-      Expression    === other                and
-      attribute     ==  other.attribute      and
-      function_sql  ==  other.function_sql   and
-      ancestor      ==  other.ancestor       and
-      @alias        ==  other.alias
-    end
-    
     module Transformations
       def as(aliaz)
         Expression.new(attribute, function_sql, aliaz, self)

lib/arel/primitives/value.rb

@@ -1,12 +1,9 @@
 module Arel
   class Value
-    attr_reader :value, :relation
-    
+    attributes :value, :relation
+    deriving :initialize, :==
     delegate :inclusion_predicate_sql, :equality_predicate_sql, :to => :value
     
-    def initialize(value, relation)
-      @value, @relation = value, relation
-    end
     
     def to_sql(formatter = Sql::WhereCondition.new(relation))
       formatter.value value
@@ -16,11 +13,6 @@ module Arel
       object.to_sql(Sql::Value.new(relation))
     end
     
-    def ==(other)
-      Value === other and
-      value ==  other.value
-    end
-    
     def bind(relation)
       Value.new(value, relation)
     end

lib/arel/relations/operations/join.rb

@@ -5,7 +5,7 @@ module Arel
     delegate :engine, :name, :to => :relation1
     hash_on :relation1
 
-    def initialize(join_sql, relation1, relation2 = Nil.new, *predicates)
+    def initialize(join_sql, relation1, relation2 = Nil.instance, *predicates)
       @join_sql, @relation1, @relation2, @predicates = join_sql, relation1, relation2, predicates
     end
     

lib/arel/relations/utilities/aggregation.rb

@@ -1,11 +1,9 @@
 module Arel
   class Aggregation < Compound
+    attributes :relation
+    deriving :initialize, :==
     include Recursion::BaseCase
 
-    def initialize(relation)
-      @relation = relation
-    end
-    
     def wheres
       []
     end
@@ -21,11 +19,6 @@ module Arel
     def name
       relation.name + '_aggregation'
     end
-    
-    def ==(other)
-      Aggregation   === other and
-      self.relation ==  other.relation
-    end
   end
   
   class Relation

lib/arel/relations/utilities/nil.rb

@@ -1,10 +1,8 @@
 module Arel
   class Nil < Relation
+    include Singleton
+    
     def table_sql(formatter = nil); '' end
     def name; '' end
-
-    def ==(other)
-      Nil === other
-    end
   end
 end

lib/arel/relations/writes/delete.rb

@@ -1,8 +1,7 @@
 module Arel
   class Deletion < Compound
-    def initialize(relation)
-      @relation = relation
-    end
+    attributes :relation
+    deriving :initialize, :==
 
     def to_sql(formatter = nil)
       [
@@ -16,10 +15,5 @@ module Arel
     def call(connection = engine.connection)
       connection.delete(to_sql)
     end
-    
-    def ==(other)
-      Deletion    === other and
-      relation    ==  other.relation
-    end
   end
 end

lib/arel/relations/writes/insert.rb

@@ -1,6 +1,7 @@
 module Arel
   class Insert < Compound
-    attr_reader :record
+    attributes :relation, :record
+    deriving :==
 
     def initialize(relation, record)
       @relation, @record = relation, record.bind(relation)
@@ -18,11 +19,5 @@ module Arel
     def call(connection = engine.connection)
       connection.insert(to_sql)
     end
-    
-    def ==(other)
-      Insert   === other         and
-      relation    == other.relation and
-      record      == other.record
-    end
   end
 end

lib/arel/relations/writes/update.rb

@@ -1,6 +1,7 @@
 module Arel
   class Update < Compound
-    attr_reader :assignments
+    attributes :relation, :assignments
+    deriving :==
     
     def initialize(relation, assignments)
       @relation, @assignments = relation, assignments.bind(relation)
@@ -20,11 +21,5 @@ module Arel
     def call(connection = engine.connection)
       connection.update(to_sql)
     end
-    
-    def ==(other)
-      Update      === other          and
-      relation    ==  other.relation and
-      assignments ==  other.assignments
-    end
   end
 end