Switch Arel::Relation to a module. This will allow for classes with Relation extended on them to represent relations themselves (as opposed to their instances being relations).

3 files changed, 5 insertions, 3 deletions

diff --git a/lib/arel/engines/memory/relations/array.rb b/lib/arel/engines/memory/relations/array.rb
index 577e327b19..6486dcbcc1 100644
--- a/lib/arel/engines/memory/relations/array.rb
+++ b/lib/arel/engines/memory/relations/array.rb
@@ -1,5 +1,7 @@
 module Arel
-  class Array < Relation
+  class Array
+    include Relation
+
     attributes :array,  :attribute_names_and_types
     include Recursion::BaseCase
     deriving :==, :initialize
diff --git a/lib/arel/engines/memory/relations/compound.rb b/lib/arel/engines/memory/relations/compound.rb
index 6dda92a6a1..0f3c24f9ec 100644
--- a/lib/arel/engines/memory/relations/compound.rb
+++ b/lib/arel/engines/memory/relations/compound.rb
@@ -1,5 +1,5 @@
 module Arel
-  class Compound < Relation
+  class Compound
     delegate :array, :to => :relation
 
     def unoperated_rows
diff --git a/lib/arel/engines/memory/relations/operations.rb b/lib/arel/engines/memory/relations/operations.rb
index a5082715a1..5d7b7670b6 100644
--- a/lib/arel/engines/memory/relations/operations.rb
+++ b/lib/arel/engines/memory/relations/operations.rb
@@ -50,7 +50,7 @@ module Arel
     end
   end
 
-  class Join < Relation
+  class Join
     def eval
       result = []
       relation1.call.each do |row1|