introduced __collect__, an internal enumerating operator. This is a map down the tree representing the relation. Monadic map to be precise

13 files changed, 61 insertions, 34 deletions

diff --git a/lib/active_relation/.DS_Store b/lib/active_relation/.DS_Store
new file mode 100644
index 0000000000..2a449ff62e
--- /dev/null
+++ b/lib/active_relation/.DS_Store
diff --git a/lib/active_relation/predicates.rb b/lib/active_relation/predicates.rb
index 76288595dc..880412fdb5 100644
--- a/lib/active_relation/predicates.rb
+++ b/lib/active_relation/predicates.rb
@@ -15,18 +15,23 @@ module ActiveRelation
     def ==(other)
       super and @attribute == other.attribute and @operand == other.operand
     end
-
-    def qualify
-      self.class.new(attribute.qualify, operand.qualify)
-    end
     
     def bind(relation)
-      self.class.new(attribute.bind(relation), operand.bind(relation))
+      __collect__{ |x| x.bind(relation) }
+    end
+    
+    def qualify
+      __collect__(&:qualify)
     end
 
     def to_sql(strategy = Sql::Predicate.new)
       "#{attribute.to_sql(strategy)} #{predicate_sql} #{operand.to_sql(strategy)}"
     end
+    
+    protected
+    def __collect__
+      self.class.new(yield(attribute), yield(operand))
+    end
   end
 
   class Equality < Binary
diff --git a/lib/active_relation/relations/aggregation.rb b/lib/active_relation/relations/aggregation.rb
index 7910223673..bcdfaa7d53 100644
--- a/lib/active_relation/relations/aggregation.rb
+++ b/lib/active_relation/relations/aggregation.rb
@@ -7,15 +7,11 @@ module ActiveRelation
     end
 
     def ==(other)
-      self.class  == other.class and
-      relation    == other.relation and
-      groupings   == other.groupings and
+      self.class  == other.class      and
+      relation    == other.relation   and
+      groupings   == other.groupings  and
       expressions == other.expressions
     end
-
-    def qualify
-      Aggregation.new(relation.qualify, :expressions => expressions.collect(&:qualify), :groupings => groupings.collect(&:qualify))
-    end
     
     def attributes
       expressions.collect { |e| e.bind(self) }
@@ -24,5 +20,10 @@ module ActiveRelation
     def aggregation?
       true
     end
+    
+    protected
+    def __collect__(&block)
+      Aggregation.new(relation.__collect__(&block), :expressions => expressions.collect(&block), :groupings => groupings.collect(&block))
+    end
   end
 end
\ No newline at end of file
diff --git a/lib/active_relation/relations/alias.rb b/lib/active_relation/relations/alias.rb
index 941a95c58e..cc6e9b09b8 100644
--- a/lib/active_relation/relations/alias.rb
+++ b/lib/active_relation/relations/alias.rb
@@ -1,15 +1,19 @@
 module ActiveRelation
   class Alias < Compound
     attr_reader :alias
+
+    def initialize(relation, aliaz)
+      @relation, @alias = relation, aliaz
+    end
     
     def aliased_prefix_for(attribute)
       self[attribute] and @alias
     end
-
-    def initialize(relation, aliaz)
-      @relation, @alias = relation, aliaz
+    
+    def __collect__(&block)
+      Alias.new(relation.__collect__(&block), @alias)
     end
-      
+
     def ==(other)
       self.class == other.class and
       relation   == other.relation and
diff --git a/lib/active_relation/relations/compound.rb b/lib/active_relation/relations/compound.rb
index d11d09fbf6..a02fbbeef5 100644
--- a/lib/active_relation/relations/compound.rb
+++ b/lib/active_relation/relations/compound.rb
@@ -8,5 +8,9 @@ module ActiveRelation
     def attributes
       relation.attributes.collect { |a| a.bind(self) }
     end
+    
+    def qualify
+      __collect__(&:qualify)
+    end
   end
 end
\ No newline at end of file
diff --git a/lib/active_relation/relations/join.rb b/lib/active_relation/relations/join.rb
index c61680fd55..a5d2b5355b 100644
--- a/lib/active_relation/relations/join.rb
+++ b/lib/active_relation/relations/join.rb
@@ -15,7 +15,7 @@ module ActiveRelation
     end
 
     def qualify
-      Join.new(join_sql, relation1.qualify, relation2.qualify, *predicates.collect(&:qualify))
+      __collect__(&:qualify)
     end
     
     def attributes
@@ -48,5 +48,9 @@ module ActiveRelation
     def table_sql
       relation1.aggregation?? relation1.to_sql(Sql::Aggregation.new) : relation1.send(:table_sql)
     end
+    
+    def __collect__(&block)
+      Join.new(join_sql, relation1.__collect__(&block), relation2.__collect__(&block), *predicates.collect(&block))
+    end
   end
 end
\ No newline at end of file
diff --git a/lib/active_relation/relations/order.rb b/lib/active_relation/relations/order.rb
index a23da967fd..90568a90ac 100644
--- a/lib/active_relation/relations/order.rb
+++ b/lib/active_relation/relations/order.rb
@@ -11,8 +11,9 @@ module ActiveRelation
       orders   == other.orders
     end
 
-    def qualify
-      Order.new(relation.qualify, *orders.collect(&:qualify))
+    protected
+    def __collect__(&block)
+      Order.new(relation.__collect__(&block), *orders.collect(&block))
     end
   end
 end
\ No newline at end of file
diff --git a/lib/active_relation/relations/projection.rb b/lib/active_relation/relations/projection.rb
index d0c68869bd..3fb594e2bb 100644
--- a/lib/active_relation/relations/projection.rb
+++ b/lib/active_relation/relations/projection.rb
@@ -15,9 +15,10 @@ module ActiveRelation
       relation    == other.relation and
       projections == other.projections
     end
-
-    def qualify
-      Projection.new(relation.qualify, *projections.collect(&:qualify))
+    
+    protected
+    def __collect__(&block)
+      Projection.new(relation.__collect__(&block), *projections.collect(&block))
     end
   end
 end
\ No newline at end of file
diff --git a/lib/active_relation/relations/range.rb b/lib/active_relation/relations/range.rb
index 7f120ab9e5..5cc5db094d 100644
--- a/lib/active_relation/relations/range.rb
+++ b/lib/active_relation/relations/range.rb
@@ -19,8 +19,9 @@ module ActiveRelation
       range.begin
     end
     
-    def qualify
-      Range.new(relation.qualify, range)
+    protected
+    def __collect__(&block)
+      Range.new(relation.__collect__(&block), range)
     end
   end
 end
\ No newline at end of file
diff --git a/lib/active_relation/relations/relation.rb b/lib/active_relation/relations/relation.rb
index c65120a75c..1c48d8be02 100644
--- a/lib/active_relation/relations/relation.rb
+++ b/lib/active_relation/relations/relation.rb
@@ -104,6 +104,10 @@ module ActiveRelation
     alias_method :to_s, :to_sql
   
     protected
+    def __collect__
+      yield self
+    end
+    
     def connection
       ActiveRecord::Base.connection
     end
diff --git a/lib/active_relation/relations/rename.rb b/lib/active_relation/relations/rename.rb
index 20e79ebefb..718dbfe30f 100644
--- a/lib/active_relation/relations/rename.rb
+++ b/lib/active_relation/relations/rename.rb
@@ -13,15 +13,16 @@ module ActiveRelation
       attribute  == other.attribute and
       pseudonym  == other.pseudonym
     end
-
-    def qualify
-      Rename.new(relation.qualify, attribute.qualify => pseudonym)
-    end
     
     def attributes
       relation.attributes.collect(&method(:baptize))
     end
     
+    protected
+    def __collect__(&block)
+      Rename.new(relation.__collect__(&block), yield(attribute) => pseudonym)
+    end
+    
     private
     def baptize(attribute)
       (attribute =~ self.attribute ? attribute.as(pseudonym) : attribute).bind(self) rescue nil
diff --git a/lib/active_relation/relations/selection.rb b/lib/active_relation/relations/selection.rb
index 98f56b0cbd..93e0e16dc5 100644
--- a/lib/active_relation/relations/selection.rb
+++ b/lib/active_relation/relations/selection.rb
@@ -12,14 +12,15 @@ module ActiveRelation
       relation   == other.relation and
       predicate  == other.predicate
     end
-
-    def qualify
-      Selection.new(relation.qualify, predicate.qualify)
-    end
-
+    
     protected
     def selects
       relation.send(:selects) + [predicate]
     end
+    
+    def __collect__(&block)
+      Selection.new(relation.__collect__(&block), yield(predicate))
+    end
+    
   end
 end
\ No newline at end of file
diff --git a/lib/active_relation/relations/table.rb b/lib/active_relation/relations/table.rb
index d85c268019..18c851c847 100644
--- a/lib/active_relation/relations/table.rb
+++ b/lib/active_relation/relations/table.rb
@@ -25,7 +25,7 @@ module ActiveRelation
     def table_sql
       "#{quote_table_name(name)}"
     end
-
+    
     private
     def qualifications
       attributes.zip(attributes.collect(&:qualified_name)).to_hash