adding outer joins

lib/arel/crud.rb

@@ -7,6 +7,7 @@ module Arel
       um = UpdateManager.new @engine
 
       if String === values
+        values = SqlLiteral.new values
         um.table @ctx.froms.last
       else
         um.table values.first.first.relation

lib/arel/nodes.rb

@@ -11,5 +11,7 @@ require 'arel/nodes/update_statement'
 require 'arel/nodes/delete_statement'
 require 'arel/nodes/unqualified_column'
 require 'arel/nodes/table_alias'
+require 'arel/nodes/join'
 require 'arel/nodes/inner_join'
+require 'arel/nodes/outer_join'
 require 'arel/nodes/on'

lib/arel/nodes/inner_join.rb

@@ -1,13 +1,6 @@
 module Arel
   module Nodes
-    class InnerJoin
-      attr_accessor :left, :right, :constraint
-
-      def initialize left, right, constraint
-        @left       = left
-        @right      = right
-        @constraint = constraint
-      end
+    class InnerJoin < Arel::Nodes::Join
     end
   end
 end

lib/arel/nodes/join.rb

@@ -0,0 +1,13 @@
+module Arel
+  module Nodes
+    class Join
+      attr_accessor :left, :right, :constraint
+
+      def initialize left, right, constraint
+        @left       = left
+        @right      = right
+        @constraint = constraint
+      end
+    end
+  end
+end

lib/arel/nodes/outer_join.rb

@@ -0,0 +1,6 @@
+module Arel
+  module Nodes
+    class OuterJoin < Arel::Nodes::Join
+    end
+  end
+end

lib/arel/select_manager.rb

@@ -19,10 +19,6 @@ module Arel
     end
 
     def project projection
-      projection = ::String == projection.class ?
-        Nodes::SqlLiteral.new(projection) :
-        projection
-
       @ctx.projections << projection
       self
     end
@@ -40,5 +36,14 @@ module Arel
       @head.limit = limit
       self
     end
+
+    def join_sql
+      viz = Visitors::ToSql.new @engine
+      @ctx.froms.grep(Nodes::Join).map { |x| viz.accept x }.join ', '
+    end
+
+    def joins manager
+      manager.join_sql
+    end
   end
 end

lib/arel/visitors/to_sql.rb

@@ -61,6 +61,10 @@ module Arel
         "#{visit o.relation} #{quote_table_name o.name}"
       end
 
+      def visit_Arel_Nodes_OuterJoin o
+        "#{visit o.left} OUTER JOIN #{visit o.right} #{visit o.constraint}"
+      end
+
       def visit_Arel_Nodes_InnerJoin o
         "#{visit o.left} INNER JOIN #{visit o.right} #{visit o.constraint}"
       end

spec/arel/select_manager_spec.rb

@@ -23,6 +23,30 @@ module Arel
   end
 
   describe 'select manager' do
+    describe 'joins' do
+      it 'returns join sql' do
+        table   = Table.new :users
+        aliaz   = table.alias
+        manager = Arel::SelectManager.new Table.engine
+        manager.from Nodes::InnerJoin.new(table, aliaz, table[:id].eq(aliaz[:id]))
+        manager.join_sql.should be_like %{
+          "users" INNER JOIN "users" "users_2" "users"."id" = "users_2"."id"
+        }
+        check manager.joins(manager).should == manager.join_sql
+      end
+
+      it 'returns outer join sql' do
+        table   = Table.new :users
+        aliaz   = table.alias
+        manager = Arel::SelectManager.new Table.engine
+        manager.from Nodes::OuterJoin.new(table, aliaz, table[:id].eq(aliaz[:id]))
+        manager.join_sql.should be_like %{
+          "users" OUTER JOIN "users" "users_2" "users"."id" = "users_2"."id"
+        }
+        check manager.joins(manager).should == manager.join_sql
+      end
+    end
+
     describe 'delete' do
       it "copies from" do
         engine  = EngineProxy.new Table.engine

spec/arel/table_spec.rb

@@ -33,14 +33,14 @@ module Arel
     describe 'take' do
       it "should add a limit" do
         manager = @relation.take 1
-        manager.project '*'
+        manager.project SqlLiteral.new '*'
         manager.to_sql.should be_like %{ SELECT * FROM "users" LIMIT 1 }
       end
     end
 
     describe 'project' do
       it 'can project' do
-        manager = @relation.project '*'
+        manager = @relation.project SqlLiteral.new '*'
         manager.to_sql.should be_like %{
           SELECT *
           FROM "users"