adding a Bin node to emit mysql BINARY keywords

lib/arel/nodes/unary.rb

@@ -10,6 +10,7 @@ module Arel
     end
 
     %w{
+      Bin
       Group
       Grouping
       Having

lib/arel/visitors/mysql.rb

@@ -2,6 +2,10 @@ module Arel
   module Visitors
     class MySQL < Arel::Visitors::ToSql
       private
+      def visit_Arel_Nodes_Bin o
+        "BINARY #{visit o.expr}"
+      end
+
       def visit_Arel_Nodes_Lock o
         visit o.expr
       end

lib/arel/visitors/to_sql.rb

@@ -133,6 +133,10 @@ key on UpdateManager using UpdateManager#key=
         ].compact.join ' '
       end
 
+      def visit_Arel_Nodes_Bin o
+        visit o.expr
+      end
+
       def visit_Arel_Nodes_With o
         "WITH #{o.children.map { |x| visit x }.join(', ')}"
       end

test/nodes/test_bin.rb

@@ -0,0 +1,23 @@
+require 'helper'
+
+module Arel
+  module Nodes
+    class TestBin < MiniTest::Unit::TestCase
+      def test_new
+        assert Arel::Nodes::Bin.new('zomg')
+      end
+
+      def test_default_to_sql
+        viz  = Arel::Visitors::ToSql.new Table.engine
+        node = Arel::Nodes::Bin.new(Arel.sql('zomg'))
+        assert_equal 'zomg', viz.accept(node)
+      end
+
+      def test_mysql_to_sql
+        viz  = Arel::Visitors::MySQL.new Table.engine
+        node = Arel::Nodes::Bin.new(Arel.sql('zomg'))
+        assert_equal 'BINARY zomg', viz.accept(node)
+      end
+    end
+  end
+end