experimenting with strategy pattern rather than conditional; not as terse, nor transparent, but i still feel it's better

12 files changed, 83 insertions, 55 deletions

diff --git a/lib/active_relation.rb b/lib/active_relation.rb
index 0b55ed74d0..23a80a9c38 100644
--- a/lib/active_relation.rb
+++ b/lib/active_relation.rb
@@ -4,7 +4,7 @@ require 'rubygems'
 require 'activesupport'
 require 'activerecord'
 
-require 'active_relation/sql_builder'
+require 'active_relation/sql'
 require 'active_relation/extensions'
 require 'active_relation/predicates'
 require 'active_relation/relations'
diff --git a/lib/active_relation/extensions/hash.rb b/lib/active_relation/extensions/hash.rb
index d9496df2e9..50864912bf 100644
--- a/lib/active_relation/extensions/hash.rb
+++ b/lib/active_relation/extensions/hash.rb
@@ -5,7 +5,7 @@ class Hash
     end
   end
   
-  def to_sql(options = {})
+  def to_sql(strategy = nil)
     "(#{values.collect(&:to_sql).join(', ')})"
   end
 end
\ No newline at end of file
diff --git a/lib/active_relation/extensions/object.rb b/lib/active_relation/extensions/object.rb
index ea582d1ca1..2d43120f70 100644
--- a/lib/active_relation/extensions/object.rb
+++ b/lib/active_relation/extensions/object.rb
@@ -1,12 +1,9 @@
 class Object
-  include ActiveRelation::SqlBuilder
-  
   def qualify
     self
   end
   
-  def to_sql(options = {})
-    options.reverse_merge!(:quote => true)
-    options[:quote] ? quote(self) : self
+  def to_sql(strategy = ActiveRelation::Sql::Scalar.new)
+    strategy.scalar self
   end
 end
\ No newline at end of file
diff --git a/lib/active_relation/predicates.rb b/lib/active_relation/predicates.rb
index fba1cc90b6..84db60e3b9 100644
--- a/lib/active_relation/predicates.rb
+++ b/lib/active_relation/predicates.rb
@@ -7,30 +7,30 @@ module ActiveRelation
     end
   
     class Binary < Base
-      attr_reader :attribute1, :attribute2
+      attr_reader :attribute, :operand
 
-      def initialize(attribute1, attribute2)
-        @attribute1, @attribute2 = attribute1, attribute2
+      def initialize(attribute, operand)
+        @attribute, @operand = attribute, operand
       end
 
       def ==(other)
-        super and @attribute1 == other.attribute1 and @attribute2 == other.attribute2
+        super and @attribute == other.attribute and @operand == other.operand
       end
 
       def qualify
-        self.class.new(attribute1.qualify, attribute2.qualify)
+        self.class.new(attribute.qualify, operand.qualify)
       end
 
-      def to_sql(options = {})
-        "#{attribute1.to_sql} #{predicate_sql} #{attribute2.to_sql}"
+      def to_sql(strategy = Sql::Predicate.new)
+        "#{attribute.to_sql(strategy)} #{predicate_sql} #{operand.to_sql(strategy)}"
       end
     end
   
     class Equality < Binary
       def ==(other)
         self.class == other.class and
-          ((attribute1 == other.attribute1 and attribute2 == other.attribute2) or
-           (attribute1 == other.attribute2 and attribute2 == other.attribute1))
+          ((attribute == other.attribute and operand == other.operand) or
+           (attribute == other.operand and operand == other.attribute))
       end
 
       protected
@@ -67,27 +67,20 @@ module ActiveRelation
       end
     end
   
-    class Match < Base
-      attr_reader :attribute, :regexp
+    class Match < Binary
+      alias_method :regexp, :operand
 
       def initialize(attribute, regexp)
         @attribute, @regexp = attribute, regexp
       end
     end
   
-    class RelationInclusion < Base
-      attr_reader :attribute, :relation
-
-      def initialize(attribute, relation)
-        @attribute, @relation = attribute, relation
-      end
-
-      def ==(other)
-        super and attribute == other.attribute and relation == other.relation
-      end
+    class RelationInclusion < Binary
+      alias_method :relation, :operand
       
-      def to_sql(options = {})
-        "#{attribute.to_sql} IN (#{relation.to_sql})"
+      protected
+      def predicate_sql
+        'IN'
       end
     end
   end
diff --git a/lib/active_relation/primitives/aggregation.rb b/lib/active_relation/primitives/aggregation.rb
index 403c03fab5..189eb33ac9 100644
--- a/lib/active_relation/primitives/aggregation.rb
+++ b/lib/active_relation/primitives/aggregation.rb
@@ -1,15 +1,13 @@
 module ActiveRelation
   module Primitives
-    class Aggregation
-      include SqlBuilder
-  
+    class Aggregation  
       attr_reader :attribute, :function_sql
       
       def initialize(attribute, function_sql)
         @attribute, @function_sql = attribute, function_sql
       end
   
-      def to_sql(options = {})
+      def to_sql(strategy = nil)
         "#{function_sql}(#{attribute.to_sql})"
       end
       
diff --git a/lib/active_relation/primitives/attribute.rb b/lib/active_relation/primitives/attribute.rb
index 5ce3dfd531..6ebaf1b292 100644
--- a/lib/active_relation/primitives/attribute.rb
+++ b/lib/active_relation/primitives/attribute.rb
@@ -1,8 +1,6 @@
 module ActiveRelation
   module Primitives
     class Attribute
-      include SqlBuilder
-  
       attr_reader :relation, :name, :alias
   
       def initialize(relation, name, aliaz = nil)
@@ -77,8 +75,8 @@ module ActiveRelation
       end
       include Aggregations
   
-      def to_sql(options = {})
-        "#{quote_table_name(relation.name)}.#{quote_column_name(name)}" + (options[:use_alias] && self.alias ? " AS #{self.alias.to_s.to_sql}" : "")
+      def to_sql(strategy = Sql::Predicate.new)
+        strategy.attribute relation.name, name, self.alias
       end
     end
   end
diff --git a/lib/active_relation/relations/base.rb b/lib/active_relation/relations/base.rb
index 71d15f31f1..c464b6bc31 100644
--- a/lib/active_relation/relations/base.rb
+++ b/lib/active_relation/relations/base.rb
@@ -1,7 +1,7 @@
 module ActiveRelation
   module Relations
     class Base
-      include SqlBuilder
+      include Sql::Quoting
   
       module Iteration
         include Enumerable
@@ -78,12 +78,12 @@ module ActiveRelation
         ActiveRecord::Base.connection
       end
   
-      def to_sql(options = {})
-        sql = [
-          "SELECT #{attributes.collect{ |a| a.to_sql(:use_alias => true) }.join(', ')}",
+      def to_sql(strategy = Sql::Select.new)
+        strategy.select [
+          "SELECT #{attributes.collect{ |a| a.to_sql(Sql::Projection.new) }.join(', ')}",
           "FROM #{table_sql}",
           (joins unless joins.blank?),
-          ("WHERE #{selects.collect{|s| s.to_sql(:quote => false)}.join("\n\tAND ")}" unless selects.blank?),
+          ("WHERE #{selects.collect{|s| s.to_sql(Sql::Predicate.new)}.join("\n\tAND ")}" unless selects.blank?),
           ("ORDER BY #{orders.collect(&:to_sql)}" unless orders.blank?),
           ("LIMIT #{limit.to_sql}" unless limit.blank?),
           ("OFFSET #{offset.to_sql}" unless offset.blank?)
diff --git a/lib/active_relation/relations/deletion.rb b/lib/active_relation/relations/deletion.rb
index 0276dc1bc4..add6440c2a 100644
--- a/lib/active_relation/relations/deletion.rb
+++ b/lib/active_relation/relations/deletion.rb
@@ -5,7 +5,7 @@ module ActiveRelation
         @relation = relation
       end
   
-      def to_sql(options = {})
+      def to_sql(strategy = nil)
         [
           "DELETE",
           "FROM #{table_sql}",
diff --git a/lib/active_relation/relations/insertion.rb b/lib/active_relation/relations/insertion.rb
index 86581c23d7..c82513ce0f 100644
--- a/lib/active_relation/relations/insertion.rb
+++ b/lib/active_relation/relations/insertion.rb
@@ -7,7 +7,7 @@ module ActiveRelation
         @relation, @record = relation, record
       end
 
-      def to_sql(options = {})
+      def to_sql(strategy = nil)
         [
           "INSERT",
           "INTO #{table_sql}",
diff --git a/lib/active_relation/relations/join.rb b/lib/active_relation/relations/join.rb
index 3d50365c40..4e6c85979e 100644
--- a/lib/active_relation/relations/join.rb
+++ b/lib/active_relation/relations/join.rb
@@ -38,7 +38,7 @@ module ActiveRelation
   
       private
       def join
-        "#{join_sql} #{relation2.send(:table_sql)} ON #{predicates.collect { |p| p.to_sql(:quote => false) }.join(' AND ')}"
+        "#{join_sql} #{relation2.send(:table_sql)} ON #{predicates.collect { |p| p.to_sql(Sql::Predicate.new) }.join(' AND ')}"
       end
     end
   end
diff --git a/lib/active_relation/sql.rb b/lib/active_relation/sql.rb
new file mode 100644
index 0000000000..89f6193cd8
--- /dev/null
+++ b/lib/active_relation/sql.rb
@@ -0,0 +1,51 @@
+module ActiveRelation
+  module Sql
+    module Quoting
+      def connection
+        ActiveRecord::Base.connection
+      end
+  
+      delegate :quote_table_name, :quote_column_name, :quote, :to => :connection
+    end
+    
+    class Strategy
+      include Quoting
+    end
+    
+    class Projection < Strategy
+      def attribute(relation_name, attribute_name, aliaz)
+        "#{quote_table_name(relation_name)}.#{quote_column_name(attribute_name)}" + (aliaz ? " AS #{quote(aliaz.to_s)}" : "")
+      end
+      
+      def select(select_sql)
+        "(#{select_sql})"
+      end
+    end
+    
+    class Predicate < Strategy
+      def attribute(relation_name, attribute_name, aliaz)
+        "#{quote_table_name(relation_name)}.#{quote_column_name(attribute_name)}"
+      end
+      
+      def scalar(scalar)
+        scalar
+      end
+      
+      def select(select_sql)
+        "(#{select_sql})"
+      end
+    end
+    
+    class Select < Strategy
+      def select(select_sql)
+        select_sql
+      end
+    end
+    
+    class Scalar < Strategy
+      def scalar(scalar)
+        quote(scalar)
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/active_relation/sql_builder.rb b/lib/active_relation/sql_builder.rb
deleted file mode 100644
index 07a4ebabb7..0000000000
--- a/lib/active_relation/sql_builder.rb
+++ /dev/null
@@ -1,9 +0,0 @@
-module ActiveRelation
-  module SqlBuilder
-    def connection
-      ActiveRecord::Base.connection
-    end
-  
-    delegate :quote_table_name, :quote_column_name, :quote, :to => :connection
-  end
-end
\ No newline at end of file