structure.rb in structure-0.28.6 vs structure.rb in structure-0.29.0

@@ -83,10 +83,18 @@
     private
 
     def attribute(name, &blk)
       name = name.to_s
       module_eval "def #{name}?; #{name}; end" if name.chomp!('?')
-      module_eval "def #{name}; return @#{name} if defined?(@#{name}); @#{name} = _#{name}.freeze; end"
+      module_eval <<-DEF
+        def #{name}
+          return @#{name} if defined?(@#{name})
+          @#{name} = _#{name}
+          @#{name}.freeze unless @#{name}.is_a?(Structure)
+
+          @#{name}
+        end
+      DEF
       define_method("_#{name}", blk)
       private "_#{name}"
 
       @attribute_names << name