reorganized file structures

Conflicts:

	lib/arel.rb
	lib/arel/arel.rb
	lib/arel/engines/memory/predicates.rb
	lib/arel/engines/memory/relations/array.rb
	lib/arel/engines/sql/relations/table.rb

55 files changed, 145 insertions, 69 deletions

diff --git a/lib/arel.rb b/lib/arel.rb
index f22287fcc5..fcca60758e 100644
--- a/lib/arel.rb
+++ b/lib/arel.rb
@@ -5,10 +5,6 @@ require 'activesupport'
 require 'activerecord'
 require 'active_record/connection_adapters/abstract/quoting'
 
-require 'arel/arel'
-require 'arel/extensions'
-require 'arel/predicates'
-require 'arel/relations'
+require 'arel/algebra'
 require 'arel/engines'
 require 'arel/session'
-require 'arel/primitives'
diff --git a/lib/arel/algebra.rb b/lib/arel/algebra.rb
new file mode 100644
index 0000000000..f27882a343
--- /dev/null
+++ b/lib/arel/algebra.rb
@@ -0,0 +1,4 @@
+require 'arel/algebra/extensions'
+require 'arel/algebra/predicates'
+require 'arel/algebra/relations'
+require 'arel/algebra/primitives'
\ No newline at end of file
diff --git a/lib/arel/algebra/extensions.rb b/lib/arel/algebra/extensions.rb
new file mode 100644
index 0000000000..5338fee989
--- /dev/null
+++ b/lib/arel/algebra/extensions.rb
@@ -0,0 +1,4 @@
+require 'arel/algebra/extensions/object'
+require 'arel/algebra/extensions/class'
+require 'arel/algebra/extensions/array'
+require 'arel/algebra/extensions/hash'
diff --git a/lib/arel/extensions/array.rb b/lib/arel/algebra/extensions/array.rb
index 5b6d6d6abd..5b6d6d6abd 100644
--- a/lib/arel/extensions/array.rb
+++ b/lib/arel/algebra/extensions/array.rb
diff --git a/lib/arel/extensions/class.rb b/lib/arel/algebra/extensions/class.rb
index f37898e7d7..f37898e7d7 100644
--- a/lib/arel/extensions/class.rb
+++ b/lib/arel/algebra/extensions/class.rb
diff --git a/lib/arel/extensions/hash.rb b/lib/arel/algebra/extensions/hash.rb
index 7472b5aa73..7472b5aa73 100644
--- a/lib/arel/extensions/hash.rb
+++ b/lib/arel/algebra/extensions/hash.rb
diff --git a/lib/arel/extensions/object.rb b/lib/arel/algebra/extensions/object.rb
index d626407dcb..d626407dcb 100644
--- a/lib/arel/extensions/object.rb
+++ b/lib/arel/algebra/extensions/object.rb
diff --git a/lib/arel/algebra/extensions/pathname.rb b/lib/arel/algebra/extensions/pathname.rb
new file mode 100644
index 0000000000..2f7e2733e7
--- /dev/null
+++ b/lib/arel/algebra/extensions/pathname.rb
@@ -0,0 +1,5 @@
+class Pathname
+  def /(path)
+    (self + path).expand_path
+  end
+end
\ No newline at end of file
diff --git a/lib/arel/algebra/predicates.rb b/lib/arel/algebra/predicates.rb
new file mode 100644
index 0000000000..f83101306e
--- /dev/null
+++ b/lib/arel/algebra/predicates.rb
@@ -0,0 +1,45 @@
+module Arel
+  class Predicate
+  end
+
+  class Binary < Predicate
+    attributes :operand1, :operand2
+    deriving :initialize
+
+    def ==(other)
+      self.class === other          and
+      @operand1  ==  other.operand1 and
+      @operand2  ==  other.operand2
+    end
+
+    def bind(relation)
+      self.class.new(operand1.find_correlate_in(relation), operand2.find_correlate_in(relation))
+    end
+  end
+
+  class Equality < Binary
+    def ==(other)
+      Equality === other and
+        ((operand1 == other.operand1 and operand2 == other.operand2) or
+         (operand1 == other.operand2 and operand2 == other.operand1))
+    end
+  end
+
+  class GreaterThanOrEqualTo < Binary
+  end
+
+  class GreaterThan < Binary
+  end
+
+  class LessThanOrEqualTo < Binary
+  end
+
+  class LessThan < Binary
+  end
+
+  class Match < Binary
+  end
+
+  class In < Binary
+  end
+end
\ No newline at end of file
diff --git a/lib/arel/algebra/primitives.rb b/lib/arel/algebra/primitives.rb
new file mode 100644
index 0000000000..a4c3169e0b
--- /dev/null
+++ b/lib/arel/algebra/primitives.rb
@@ -0,0 +1,4 @@
+require 'arel/algebra/primitives/attribute'
+require 'arel/algebra/primitives/value'
+require 'arel/algebra/primitives/expression'
+
diff --git a/lib/arel/primitives/attribute.rb b/lib/arel/algebra/primitives/attribute.rb
index 5e216770e4..5e216770e4 100644
--- a/lib/arel/primitives/attribute.rb
+++ b/lib/arel/algebra/primitives/attribute.rb
diff --git a/lib/arel/primitives/expression.rb b/lib/arel/algebra/primitives/expression.rb
index b67a5e1f8e..b67a5e1f8e 100644
--- a/lib/arel/primitives/expression.rb
+++ b/lib/arel/algebra/primitives/expression.rb
diff --git a/lib/arel/primitives/value.rb b/lib/arel/algebra/primitives/value.rb
index 91c4045507..91c4045507 100644
--- a/lib/arel/primitives/value.rb
+++ b/lib/arel/algebra/primitives/value.rb
diff --git a/lib/arel/algebra/relations.rb b/lib/arel/algebra/relations.rb
new file mode 100644
index 0000000000..03f04d2459
--- /dev/null
+++ b/lib/arel/algebra/relations.rb
@@ -0,0 +1,15 @@
+require 'arel/algebra/relations/relation'
+require 'arel/algebra/relations/utilities/compound'
+require 'arel/algebra/relations/utilities/nil'
+require 'arel/algebra/relations/utilities/externalization'
+require 'arel/algebra/relations/writes/delete'
+require 'arel/algebra/relations/writes/update'
+require 'arel/algebra/relations/writes/insert'
+require 'arel/algebra/relations/operations/alias'
+require 'arel/algebra/relations/operations/group'
+require 'arel/algebra/relations/operations/join'
+require 'arel/algebra/relations/operations/order'
+require 'arel/algebra/relations/operations/project'
+require 'arel/algebra/relations/operations/where'
+require 'arel/algebra/relations/operations/skip'
+require 'arel/algebra/relations/operations/take'
\ No newline at end of file
diff --git a/lib/arel/relations/operations/alias.rb b/lib/arel/algebra/relations/operations/alias.rb
index 67837f6a75..67837f6a75 100644
--- a/lib/arel/relations/operations/alias.rb
+++ b/lib/arel/algebra/relations/operations/alias.rb
diff --git a/lib/arel/relations/operations/group.rb b/lib/arel/algebra/relations/operations/group.rb
index 04fd9fea62..04fd9fea62 100644
--- a/lib/arel/relations/operations/group.rb
+++ b/lib/arel/algebra/relations/operations/group.rb
diff --git a/lib/arel/relations/operations/join.rb b/lib/arel/algebra/relations/operations/join.rb
index 8e19254378..8e19254378 100644
--- a/lib/arel/relations/operations/join.rb
+++ b/lib/arel/algebra/relations/operations/join.rb
diff --git a/lib/arel/relations/operations/order.rb b/lib/arel/algebra/relations/operations/order.rb
index 05af3fde4d..05af3fde4d 100644
--- a/lib/arel/relations/operations/order.rb
+++ b/lib/arel/algebra/relations/operations/order.rb
diff --git a/lib/arel/relations/operations/project.rb b/lib/arel/algebra/relations/operations/project.rb
index 5507ea3163..5507ea3163 100644
--- a/lib/arel/relations/operations/project.rb
+++ b/lib/arel/algebra/relations/operations/project.rb
diff --git a/lib/arel/relations/operations/skip.rb b/lib/arel/algebra/relations/operations/skip.rb
index 930e4c94ea..930e4c94ea 100644
--- a/lib/arel/relations/operations/skip.rb
+++ b/lib/arel/algebra/relations/operations/skip.rb
diff --git a/lib/arel/relations/operations/take.rb b/lib/arel/algebra/relations/operations/take.rb
index 2fd3fdf635..2fd3fdf635 100644
--- a/lib/arel/relations/operations/take.rb
+++ b/lib/arel/algebra/relations/operations/take.rb
diff --git a/lib/arel/relations/operations/where.rb b/lib/arel/algebra/relations/operations/where.rb
index 608aaeb4b7..608aaeb4b7 100644
--- a/lib/arel/relations/operations/where.rb
+++ b/lib/arel/algebra/relations/operations/where.rb
diff --git a/lib/arel/relations/relation.rb b/lib/arel/algebra/relations/relation.rb
index 20badaf165..20badaf165 100644
--- a/lib/arel/relations/relation.rb
+++ b/lib/arel/algebra/relations/relation.rb
diff --git a/lib/arel/relations/utilities/compound.rb b/lib/arel/algebra/relations/utilities/compound.rb
index b1e8054d4d..e33b8dbf14 100644
--- a/lib/arel/relations/utilities/compound.rb
+++ b/lib/arel/algebra/relations/utilities/compound.rb
@@ -3,7 +3,7 @@ module Arel
     attr_reader :relation
     hash_on :relation
     delegate :joins, :join?, :inserts, :taken, :skipped, :name, :externalizable?,
-             :column_for, :engine, :table, :table_sql,
+             :column_for, :engine, :table, :table_sql, :array,
              :to => :relation
 
     [:attributes, :wheres, :groupings, :orders].each do |operation_name|
diff --git a/lib/arel/relations/utilities/externalization.rb b/lib/arel/algebra/relations/utilities/externalization.rb
index bd067f2304..bd067f2304 100644
--- a/lib/arel/relations/utilities/externalization.rb
+++ b/lib/arel/algebra/relations/utilities/externalization.rb
diff --git a/lib/arel/relations/utilities/nil.rb b/lib/arel/algebra/relations/utilities/nil.rb
index 6a9d678c45..6a9d678c45 100644
--- a/lib/arel/relations/utilities/nil.rb
+++ b/lib/arel/algebra/relations/utilities/nil.rb
diff --git a/lib/arel/relations/writes/delete.rb b/lib/arel/algebra/relations/writes/delete.rb
index a94067c7fa..a94067c7fa 100644
--- a/lib/arel/relations/writes/delete.rb
+++ b/lib/arel/algebra/relations/writes/delete.rb
diff --git a/lib/arel/relations/writes/insert.rb b/lib/arel/algebra/relations/writes/insert.rb
index 6d85e9769a..6d85e9769a 100644
--- a/lib/arel/relations/writes/insert.rb
+++ b/lib/arel/algebra/relations/writes/insert.rb
diff --git a/lib/arel/relations/writes/update.rb b/lib/arel/algebra/relations/writes/update.rb
index e647218a80..e647218a80 100644
--- a/lib/arel/relations/writes/update.rb
+++ b/lib/arel/algebra/relations/writes/update.rb
diff --git a/lib/arel/arel.rb b/lib/arel/arel.rb
deleted file mode 100644
index 7780d45e25..0000000000
--- a/lib/arel/arel.rb
+++ /dev/null
@@ -1,3 +0,0 @@
-def Arel(name, engine = (Arel::Table.engine || ActiveRecord::Base.connection))
-  Arel::Table.new(name, engine)
-end
diff --git a/lib/arel/engines.rb b/lib/arel/engines.rb
index 63a929528f..3f854edf90 100644
--- a/lib/arel/engines.rb
+++ b/lib/arel/engines.rb
@@ -1,2 +1,2 @@
-require 'arel/engines/sql/sql'
-require 'arel/engines/array/array'
\ No newline at end of file
+require 'arel/engines/sql'
+require 'arel/engines/memory'
\ No newline at end of file
diff --git a/lib/arel/engines/array/array.rb b/lib/arel/engines/array/array.rb
deleted file mode 100644
index 3a3a47308a..0000000000
--- a/lib/arel/engines/array/array.rb
+++ /dev/null
@@ -1 +0,0 @@
-require 'arel/engines/array/relations/array'
\ No newline at end of file
diff --git a/lib/arel/engines/memory.rb b/lib/arel/engines/memory.rb
new file mode 100644
index 0000000000..df6f6f3d48
--- /dev/null
+++ b/lib/arel/engines/memory.rb
@@ -0,0 +1,4 @@
+require 'arel/engines/memory/relations'
+require 'arel/engines/memory/primitives'
+require 'arel/engines/memory/engine'
+require 'arel/engines/memory/predicates'
\ No newline at end of file
diff --git a/lib/arel/engines/memory/engine.rb b/lib/arel/engines/memory/engine.rb
new file mode 100644
index 0000000000..67a084f2cd
--- /dev/null
+++ b/lib/arel/engines/memory/engine.rb
@@ -0,0 +1,12 @@
+module Arel
+  module Memory
+    class Engine
+      module CRUD
+        def read(relation)
+          relation.eval
+        end
+      end
+      include CRUD
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/arel/predicates.rb b/lib/arel/engines/memory/predicates.rb
index aa206d4e96..3522ea3ffa 100644
--- a/lib/arel/predicates.rb
+++ b/lib/arel/engines/memory/predicates.rb
@@ -10,17 +10,8 @@ module Arel
   end
 
   class Binary < Predicate
-    attributes :operand1, :operand2
-    deriving :initialize
-
-    def ==(other)
-      self.class === other          and
-      @operand1  ==  other.operand1 and
-      @operand2  ==  other.operand2
-    end
-
-    def bind(relation)
-      self.class.new(operand1.find_correlate_in(relation), operand2.find_correlate_in(relation))
+    def eval(row)
+      operand1.eval(row).send(operator, operand2.eval(row))
     end
   end
 
@@ -56,6 +47,7 @@ module Arel
   end
 
   class LessThan < Binary
+    def operator; :< end
   end
 
   class Match < Binary
diff --git a/lib/arel/engines/memory/primitives.rb b/lib/arel/engines/memory/primitives.rb
new file mode 100644
index 0000000000..4d5c76e956
--- /dev/null
+++ b/lib/arel/engines/memory/primitives.rb
@@ -0,0 +1,2 @@
+require 'arel/engines/memory/primitives/attribute'
+require 'arel/engines/memory/primitives/value'
diff --git a/lib/arel/engines/memory/primitives/attribute.rb b/lib/arel/engines/memory/primitives/attribute.rb
new file mode 100644
index 0000000000..9864feadc2
--- /dev/null
+++ b/lib/arel/engines/memory/primitives/attribute.rb
@@ -0,0 +1,7 @@
+module Arel
+  class Attribute
+    def eval(row)
+      row[self]
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/arel/engines/memory/primitives/value.rb b/lib/arel/engines/memory/primitives/value.rb
new file mode 100644
index 0000000000..b83cd02e57
--- /dev/null
+++ b/lib/arel/engines/memory/primitives/value.rb
@@ -0,0 +1,7 @@
+module Arel
+  class Value
+    def eval(row)
+      value
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/arel/engines/memory/relations.rb b/lib/arel/engines/memory/relations.rb
new file mode 100644
index 0000000000..6361d7c9d7
--- /dev/null
+++ b/lib/arel/engines/memory/relations.rb
@@ -0,0 +1,2 @@
+require 'arel/engines/memory/relations/array'
+require 'arel/engines/memory/relations/operations/where'
diff --git a/lib/arel/engines/array/relations/array.rb b/lib/arel/engines/memory/relations/array.rb
index dac65abbc2..c02c62891b 100644
--- a/lib/arel/engines/array/relations/array.rb
+++ b/lib/arel/engines/memory/relations/array.rb
@@ -1,9 +1,11 @@
 module Arel
   class Array < Relation
+    attributes :array,  :attribute_names
+    deriving :initialize
     include Recursion::BaseCase
-
-    def initialize(array, attribute_names)
-      @array, @attribute_names = array, attribute_names
+    
+    def engine
+      @engine ||= Memory::Engine.new
     end
 
     def attributes
@@ -12,7 +14,7 @@ module Arel
       end
     end
 
-    def call(connection = nil)
+    def eval
       @array.collect { |row| attributes.zip(row).to_hash }
     end
   end
diff --git a/lib/arel/engines/memory/relations/operations/where.rb b/lib/arel/engines/memory/relations/operations/where.rb
new file mode 100644
index 0000000000..eb11fb55fd
--- /dev/null
+++ b/lib/arel/engines/memory/relations/operations/where.rb
@@ -0,0 +1,7 @@
+module Arel
+  class Where < Compound
+    def eval
+      relation.eval.select { |row| predicate.eval(row) }
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/arel/engines/sql/sql.rb b/lib/arel/engines/sql.rb
index aed1fd861e..aed1fd861e 100644
--- a/lib/arel/engines/sql/sql.rb
+++ b/lib/arel/engines/sql.rb
diff --git a/lib/arel/engines/sql/primitives/attribute.rb b/lib/arel/engines/sql/primitives/attribute.rb
index 48de690b6f..ad78a9ec5b 100644
--- a/lib/arel/engines/sql/primitives/attribute.rb
+++ b/lib/arel/engines/sql/primitives/attribute.rb
@@ -1,5 +1,3 @@
-require 'set'
-
 module Arel
   class Attribute
     def column
diff --git a/lib/arel/engines/sql/relations.rb b/lib/arel/engines/sql/relations.rb
index 4de01b2691..39ef8852a1 100644
--- a/lib/arel/engines/sql/relations.rb
+++ b/lib/arel/engines/sql/relations.rb
@@ -1,5 +1,10 @@
-require 'arel/engines/sql/relations/utilities'
+require 'arel/engines/sql/relations/utilities/recursion'
+require 'arel/engines/sql/relations/utilities/externalization'
+require 'arel/engines/sql/relations/utilities/nil'
 require 'arel/engines/sql/relations/relation'
-require 'arel/engines/sql/relations/operations'
-require 'arel/engines/sql/relations/writes'
-require 'arel/engines/sql/relations/table'
\ No newline at end of file
+require 'arel/engines/sql/relations/table'
+require 'arel/engines/sql/relations/operations/join'
+require 'arel/engines/sql/relations/operations/alias'
+require 'arel/engines/sql/relations/writes/delete'
+require 'arel/engines/sql/relations/writes/insert'
+require 'arel/engines/sql/relations/writes/update'
\ No newline at end of file
diff --git a/lib/arel/engines/sql/relations/operations.rb b/lib/arel/engines/sql/relations/operations.rb
deleted file mode 100644
index ff33fc6bc3..0000000000
--- a/lib/arel/engines/sql/relations/operations.rb
+++ /dev/null
@@ -1,2 +0,0 @@
-require 'arel/engines/sql/relations/operations/alias'
-require 'arel/engines/sql/relations/operations/join'
diff --git a/lib/arel/engines/sql/relations/table.rb b/lib/arel/engines/sql/relations/table.rb
index 0433abbbb2..2653744149 100644
--- a/lib/arel/engines/sql/relations/table.rb
+++ b/lib/arel/engines/sql/relations/table.rb
@@ -34,3 +34,8 @@ module Arel
     end
   end
 end
+
+def Table(name, engine = Arel::Table.engine)
+  Arel::Table.new(name, engine)
+end
+
diff --git a/lib/arel/engines/sql/relations/utilities.rb b/lib/arel/engines/sql/relations/utilities.rb
deleted file mode 100644
index a1451ed448..0000000000
--- a/lib/arel/engines/sql/relations/utilities.rb
+++ /dev/null
@@ -1,3 +0,0 @@
-require 'arel/engines/sql/relations/utilities/recursion'
-require 'arel/engines/sql/relations/utilities/externalization'
-require 'arel/engines/sql/relations/utilities/nil'
diff --git a/lib/arel/engines/sql/relations/writes.rb b/lib/arel/engines/sql/relations/writes.rb
deleted file mode 100644
index dcadc326d9..0000000000
--- a/lib/arel/engines/sql/relations/writes.rb
+++ /dev/null
@@ -1,3 +0,0 @@
-require 'arel/engines/sql/relations/writes/delete'
-require 'arel/engines/sql/relations/writes/insert'
-require 'arel/engines/sql/relations/writes/update'
diff --git a/lib/arel/extensions.rb b/lib/arel/extensions.rb
deleted file mode 100644
index 299ba0631c..0000000000
--- a/lib/arel/extensions.rb
+++ /dev/null
@@ -1,4 +0,0 @@
-require 'arel/extensions/object'
-require 'arel/extensions/class'
-require 'arel/extensions/array'
-require 'arel/extensions/hash'
diff --git a/lib/arel/primitives.rb b/lib/arel/primitives.rb
deleted file mode 100644
index d84713d3d5..0000000000
--- a/lib/arel/primitives.rb
+++ /dev/null
@@ -1,4 +0,0 @@
-require 'arel/primitives/attribute'
-require 'arel/primitives/value'
-require 'arel/primitives/expression'
-
diff --git a/lib/arel/relations.rb b/lib/arel/relations.rb
deleted file mode 100644
index f97c35e56e..0000000000
--- a/lib/arel/relations.rb
+++ /dev/null
@@ -1,4 +0,0 @@
-require 'arel/relations/relation'
-require 'arel/relations/utilities'
-require 'arel/relations/writes'
-require 'arel/relations/operations'
\ No newline at end of file
diff --git a/lib/arel/relations/operations.rb b/lib/arel/relations/operations.rb
deleted file mode 100644
index c598c7fcc9..0000000000
--- a/lib/arel/relations/operations.rb
+++ /dev/null
@@ -1,8 +0,0 @@
-require 'arel/relations/operations/alias'
-require 'arel/relations/operations/group'
-require 'arel/relations/operations/join'
-require 'arel/relations/operations/order'
-require 'arel/relations/operations/project'
-require 'arel/relations/operations/where'
-require 'arel/relations/operations/skip'
-require 'arel/relations/operations/take'
\ No newline at end of file
diff --git a/lib/arel/relations/utilities.rb b/lib/arel/relations/utilities.rb
deleted file mode 100644
index fbd949ef0c..0000000000
--- a/lib/arel/relations/utilities.rb
+++ /dev/null
@@ -1,3 +0,0 @@
-require 'arel/relations/utilities/compound'
-require 'arel/relations/utilities/nil'
-require 'arel/relations/utilities/externalization'
diff --git a/lib/arel/relations/writes.rb b/lib/arel/relations/writes.rb
deleted file mode 100644
index 1495d9c857..0000000000
--- a/lib/arel/relations/writes.rb
+++ /dev/null
@@ -1,3 +0,0 @@
-require 'arel/relations/writes/delete'
-require 'arel/relations/writes/update'
-require 'arel/relations/writes/insert'
\ No newline at end of file
diff --git a/lib/arel/session.rb b/lib/arel/session.rb
index 9c2ddc535b..cf04e8a93a 100644
--- a/lib/arel/session.rb
+++ b/lib/arel/session.rb
@@ -1,5 +1,3 @@
-require 'singleton'
-
 module Arel
   class Session
     class << self