text: var o_writer = require('./o-writer.js');
  var o_reader = require('./o-reader.js');
  
  module.exports = function (key, def) {
      def = def || {};
      def.writer = def.writer || o_writer( key, def );
      def.reader = def.reader || o_reader( key, def );
  
      return function (val) {
          if (val !== undefined) return def.writer.call( this, val );
          return def.reader.call( this );
      };
  };
  