Merge pull request #56 from dcadenas/master

Add nodes that represent boolean constants

lib/arel/factory_methods.rb

@@ -2,6 +2,14 @@ module Arel
   ###
   # Methods for creating various nodes
   module FactoryMethods
+    def create_true
+      Arel::Nodes::True.new
+    end
+
+    def create_false
+      Arel::Nodes::False.new
+    end
+
     def create_table_alias relation, name
       Nodes::TableAlias.new(relation, name)
     end

lib/arel/nodes.rb

@@ -8,6 +8,8 @@
 # terminal
 
 require 'arel/nodes/terminal'
+require 'arel/nodes/true'
+require 'arel/nodes/false'
 
 # unary
 require 'arel/nodes/unary'

lib/arel/nodes/false.rb

@@ -0,0 +1,6 @@
+module Arel
+  module Nodes
+    class False < Arel::Nodes::Node
+    end
+  end
+end

lib/arel/nodes/true.rb

@@ -0,0 +1,6 @@
+module Arel
+  module Nodes
+    class True < Arel::Nodes::Node
+    end
+  end
+end

lib/arel/predications.rb

@@ -1,6 +1,5 @@
 module Arel
   module Predications
-
     def not_eq other
       Nodes::NotEqual.new self, other
     end

lib/arel/visitors/to_sql.rb

@@ -90,6 +90,14 @@ def visit_Arel_Nodes_Exists o
           o.alias ? " AS #{visit o.alias}" : ''}"
       end
 
+      def visit_Arel_Nodes_True o
+        "TRUE"
+      end
+
+      def visit_Arel_Nodes_False o
+        "FALSE"
+      end
+
       def table_exists? name
         @pool.table_exists? name
       end

test/test_factory_methods.rb

@@ -23,6 +23,16 @@ def test_create_on
         assert_equal :one, on.expr
       end
 
+      def test_create_true
+        true_node = @factory.create_true
+        assert_instance_of Nodes::True, true_node
+      end
+
+      def test_create_false
+        false_node = @factory.create_false
+        assert_instance_of Nodes::False, false_node
+      end
+
       def test_lower
         lower = @factory.lower :one
         assert_instance_of Nodes::NamedFunction, lower

test/visitors/test_to_sql.rb

@@ -325,6 +325,22 @@ def quote value, column = nil
         end
       end
 
+      describe 'Constants' do
+        it "should handle true" do
+          test = Table.new(:users).create_true
+          @visitor.accept(test).must_be_like %{
+            TRUE
+          }
+        end
+
+        it "should handle false" do
+          test = Table.new(:users).create_false
+          @visitor.accept(test).must_be_like %{
+            FALSE
+          }
+        end
+      end
+
       describe 'TableAlias' do
         it "should use the underlying table for checking columns" do
           test = Table.new(:users).alias('zomgusers')[:id].eq '3'