rem: rv += rv ? ", " + p : p; 
add: rv.push(p); 
context: function keys (o){    var rv = "";        for (var p in o)        rv += rv ? ", " + p : p;    return rv;    }
meta: 1567	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/1567/d48f16433de56d67c17f622c4f28d42121e461fc/utils.js/buggy/js/lib/utils.js