adding order clauses method to the select manager

lib/arel.rb

@@ -26,4 +26,5 @@
 
 require 'arel/visitors/to_sql'
 require 'arel/visitors/join_sql'
+require 'arel/visitors/order_clauses'
 require 'arel/visitors/dot'

lib/arel/select_manager.rb

@@ -29,7 +29,10 @@ def where expr
     end
 
     def order *expr
-      @head.orders.concat expr
+      # FIXME: We SHOULD NOT be converting these to SqlLiteral automatically
+      @head.orders.concat expr.map { |x|
+        String === x ? Nodes::SqlLiteral.new(x) : x
+      }
       self
     end
 
@@ -47,6 +50,10 @@ def join_sql
       Nodes::SqlLiteral.new viz.accept @ctx
     end
 
+    def order_clauses
+      Visitors::OrderClauses.new(@engine).accept @head
+    end
+
     def joins manager
       manager.join_sql
     end

lib/arel/visitors/order_clauses.rb

+module Arel
+  module Visitors
+    class OrderClauses < Arel::Visitors::ToSql
+      def visit_Arel_Nodes_SelectStatement o
+        o.orders.map { |x| visit x }
+      end
+    end
+  end
+end

lib/arel/visitors/to_sql.rb

@@ -126,8 +126,8 @@ def visit_Time o; quote(o) end
 
       DISPATCH = {}
       def visit object
-        send "visit_#{object.class.name.gsub('::', '_')}", object
-        #send DISPATCH[object.class], object
+        #send "visit_#{object.class.name.gsub('::', '_')}", object
+        send DISPATCH[object.class], object
       end
 
       private_instance_methods(false).each do |method|

spec/arel/select_manager_spec.rb

@@ -80,6 +80,17 @@ def execute sql, name = nil
       end
     end
 
+    describe 'order_clauses' do
+      it 'returns order clauses as a list' do
+        table   = Table.new :users
+        aliaz   = table.alias
+        manager = Arel::SelectManager.new Table.engine
+        manager.from table
+        manager.order table[:id]
+        manager.order_clauses.first.should be_like %{ "users"."id" }
+      end
+    end
+
     describe 'delete' do
       it "copies from" do
         engine  = EngineProxy.new Table.engine