def probe(jstext): jsast = jsparser.parse(jstext,lexer=jslexer) try: good_result = jsinterpgood.interpret(jsast) except: good_result = "error!" try: buggy_result = jsinterpbuggy.interpret(jsast) except: buggy_result = "error!" print jstext if good_result == buggy_result: # not interesting print "\tgood = buggy = ", good_result else: # very interesting! print "\tgood = ", good_result print "\tbuggy = ", buggy_result