adding an AS node

History.txt

@@ -4,6 +4,7 @@
 
   * #lock will lock SELECT statements "FOR UPDATE" on mysql
   * Nodes::Node#not factory method added for creating Nodes::Not nodes
+  * Added an As node
 
 == 2.0.4
 

Manifest.txt

@@ -17,6 +17,7 @@ lib/arel/expressions.rb
 lib/arel/insert_manager.rb
 lib/arel/nodes.rb
 lib/arel/nodes/and.rb
+lib/arel/nodes/as.rb
 lib/arel/nodes/assignment.rb
 lib/arel/nodes/avg.rb
 lib/arel/nodes/between.rb
@@ -81,6 +82,7 @@ lib/arel/visitors/visitor.rb
 lib/arel/visitors/where_sql.rb
 test/attributes/test_attribute.rb
 test/helper.rb
+test/nodes/test_as.rb
 test/nodes/test_count.rb
 test/nodes/test_delete_statement.rb
 test/nodes/test_equality.rb

lib/arel/nodes.rb

@@ -6,6 +6,7 @@ require 'arel/nodes/not_equal'
 require 'arel/nodes/assignment'
 require 'arel/nodes/or'
 require 'arel/nodes/and'
+require 'arel/nodes/as'
 require 'arel/nodes/not'
 require 'arel/nodes/greater_than'
 require 'arel/nodes/greater_than_or_equal'

lib/arel/nodes/as.rb

@@ -0,0 +1,6 @@
+module Arel
+  module Nodes
+    class As < Arel::Nodes::Binary
+    end
+  end
+end

lib/arel/predications.rb

@@ -1,5 +1,9 @@
 module Arel
   module Predications
+    def as other
+      Nodes::As.new self, other
+    end
+
     def not_eq other
       Nodes::NotEqual.new self, other
     end
@@ -174,4 +178,4 @@ module Arel
       }
     end
   end
-end
+end

lib/arel/visitors/to_sql.rb

@@ -250,6 +250,10 @@ module Arel
         end
       end
 
+      def visit_Arel_Nodes_As o
+        "#{visit o.left} AS #{visit o.right}"
+      end
+
       def visit_Arel_Nodes_UnqualifiedColumn o
         "#{quote_column_name o.name}"
       end

test/nodes/test_as.rb

@@ -0,0 +1,16 @@
+require 'helper'
+
+module Arel
+  module Nodes
+    describe 'As' do
+      describe '#as' do
+        it 'makes an AS node' do
+          attr = Table.new(:users)[:id]
+          as = attr.as(Arel.sql('foo'))
+          assert_equal attr, as.left
+          assert_equal 'foo', as.right
+        end
+      end
+    end
+  end
+end

test/visitors/test_to_sql.rb

@@ -38,6 +38,12 @@ module Arel
         sql.must_be_like "NOT foo"
       end
 
+      it "should visit_As" do
+        as = Nodes::As.new(Arel.sql("foo"), Arel.sql("bar"))
+        sql = @visitor.accept as
+        sql.must_be_like "foo AS bar"
+      end
+
       it "should visit_Bignum" do
         @visitor.accept 8787878092
       end