1 files changed, 97 insertions, 0 deletions
diff --git a/lib/arel/sql.rb b/lib/arel/sql.rb
new file mode 100644
index 0000000000..b6d646c047
--- /dev/null
+++ b/lib/arel/sql.rb
@@ -0,0 +1,97 @@
+module Arel
+  module Sql
+    module Quoting
+      delegate :quote_table_name, :quote_column_name, :quote, :to => :engine
+    end
+    
+    class Formatter
+      attr_reader :engine
+      
+      include Quoting
+      
+      def initialize(engine)
+        @engine = engine
+      end
+    end
+    
+    class SelectClause < Formatter
+      def attribute(relation_name, attribute_name, aliaz)
+        "#{quote_table_name(relation_name)}.#{quote_column_name(attribute_name)}" + (aliaz ? " AS #{quote(aliaz.to_s)}" : "")
+      end
+      
+      def select(select_sql, aliaz)
+        "(#{select_sql})" + (aliaz ? " AS #{quote(aliaz)}" : "")
+      end
+      
+      def value(value)
+        value
+      end
+    end
+    
+    class PassThrough < Formatter
+      def value(value)
+        value
+      end
+    end
+    
+    class WhereClause < PassThrough
+    end
+    
+    class OrderClause < PassThrough
+      def attribute(relation_name, attribute_name, aliaz)
+        "#{quote_table_name(relation_name)}.#{quote_column_name(attribute_name)}"
+      end
+    end
+    
+    class WhereCondition < Formatter
+      def attribute(relation_name, attribute_name, aliaz)
+        "#{quote_table_name(relation_name)}.#{quote_column_name(attribute_name)}"
+      end
+      
+      def value(value)
+        value.to_sql(self)
+      end
+      
+      def scalar(value, column = nil)
+        quote(value, column)
+      end
+      
+      def select(select_sql, aliaz)
+        "(#{select_sql})"
+      end
+    end
+    
+    class SelectStatement < Formatter
+      def select(select_sql, aliaz)
+        select_sql
+      end
+    end
+    
+    class TableReference < Formatter
+      def select(select_sql, aliaz)
+        "(#{select_sql}) AS #{quote_table_name(aliaz)}"
+      end
+    end
+    
+    class Attribute < WhereCondition
+      def initialize(attribute)
+        @attribute, @engine = attribute, attribute.engine
+      end
+      
+      def scalar(scalar)
+        quote(scalar, @attribute.column)
+      end
+      
+      def array(array)
+        "(" + array.collect { |e| e.to_sql(self) }.join(', ') + ")"
+      end
+      
+      def range(left, right)
+        "#{left} AND #{right}"
+      end
+    end
+    
+    class Value < WhereCondition
+    end
+  end
+end
+\ No newline at end of file