michael@0: var OMIT = {};
michael@0: var WRITABLES = [true, false, OMIT];
michael@0: {
michael@0:   var desc = {};
michael@0:   function put(field, value)
michael@0:     desc[field] = value;
michael@0:   WRITABLES.forEach(function(writable) {
michael@0:     put("writable", writable)
michael@0:   });
michael@0: };