From d827d6e9ee10fa0906b7b3cfd191e6f9ac5d6b08 Mon Sep 17 00:00:00 2001
From: Aaron Patterson <aaron.patterson@gmail.com>
Date: Thu, 12 Aug 2010 15:40:58 -0700
Subject: to_sql visitor started

---
 lib/arel/nodes/equality.rb  |  5 +++++
 lib/arel/table.rb           |  2 ++
 lib/arel/visitors/to_sql.rb | 38 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 45 insertions(+)
 create mode 100644 lib/arel/visitors/to_sql.rb

(limited to 'lib/arel')

diff --git a/lib/arel/nodes/equality.rb b/lib/arel/nodes/equality.rb
index 11383b1d89..d778380054 100644
--- a/lib/arel/nodes/equality.rb
+++ b/lib/arel/nodes/equality.rb
@@ -7,6 +7,11 @@ module Arel
         @left  = left
         @right = right
       end
+
+      def to_sql
+        viz = Visitors::ToSql.new left.relation.engine
+        viz.accept self
+      end
     end
   end
 end
diff --git a/lib/arel/table.rb b/lib/arel/table.rb
index 78b3ea9933..0ab39f134d 100644
--- a/lib/arel/table.rb
+++ b/lib/arel/table.rb
@@ -3,6 +3,8 @@ module Arel
     @engine = nil
     class << self; attr_accessor :engine; end
 
+    attr_reader :name, :engine
+
     def initialize name, engine = Table.engine
       @name   = name
       @engine = engine
diff --git a/lib/arel/visitors/to_sql.rb b/lib/arel/visitors/to_sql.rb
new file mode 100644
index 0000000000..ba92ca7ef1
--- /dev/null
+++ b/lib/arel/visitors/to_sql.rb
@@ -0,0 +1,38 @@
+module Arel
+  module Visitors
+    class ToSql
+      def initialize engine
+        @engine     = engine
+        @connection = nil
+      end
+
+      def accept object
+        @connection = @engine.connection
+        visit object
+      end
+
+      private
+      def visit_Arel_Nodes_Equality o
+        "#{visit o.left} = #{visit o.right}"
+      end
+
+      def visit_Arel_Attributes_Integer o
+        "#{quote_table_name o.relation.name}.#{quote_column_name o.name}"
+      end
+
+      def visit_Fixnum o; o end
+
+      def visit object
+        send :"visit_#{object.class.name.gsub('::', '_')}", object
+      end
+
+      def quote_table_name name
+        @connection.quote_table_name name
+      end
+
+      def quote_column_name name
+        @connection.quote_column_name name
+      end
+    end
+  end
+end
-- 
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