Errata for Python Cookbook

cls._inst = type.__new__(cls, *args, **kwargs) NOW READS: cls._inst = super(Singleton, cls).__new__(cls, *args, **kwargs)

The 'eggs' parameter passed when trying to instantiate s2...Singleton! NOW READS: The 'spam' parameter originally passed when s1 was instantiated has now been trampled upon by the re-instantiation -- that's part of the price you pay for having a Singleton!

lines 1, 3 and 5: os.F_GETFL and os.F_SETFL were incorrect. The code NOW READS: fl = fcntl.fcntl(fd,fcntl.F_GETFL) try: fcntl.fcntl(fd, fcntl.F_SETFL, fl | os.O_NDELAY) except AttributeError: fcntl.fcntl(fd, fcntl.F_SETFL, fl | os.FNDELAY)

In this code: def EndElement(self, name): 'Expat end element event handler' self.nodeStack[-1].pop( ) the last line is wrong. It should read: self.nodeStack.pop( )

The source in the book and in the samples zip file is: rx_headers = re.compile('|'.join(headers), re.IGNORECASE) but it should be to work properly (it's case sensitive): rx_headers = re.compile('|'.join(HEADERS), re.IGNORECASE)

Site that is referred to does not exist any more; new site is at http://www.dabeaz.com/ply/

obj = super(MetaAuto, cls).__call__(cls, *a, **k) should be changed to obj = super(MetaAuto, cls).__call__() AUTHOR'S REPLY: The reader's observation is ALMOST correct; the proper expression is neither the one in the book, nor the one he suggests, but rather the following one: obj = super(MetaAuto, cls).__call__(*a, **k) To check this, the reader can run, for example, the following code (together with what he can find in cb2_20_14_exm_3.py in the zipfile of all code in the book, available at http://examples.oreilly.com/ 9780596007973/cb2_examples.zip ): class named_recorder(auto_object): count = 0 events = attr(list) def __init__(self, name): self.name = name def __str__(self): return '%s: [%s] %s' % (self.name, self.count, self.events) def record(self, event): self.count += 1 self.events.append((self.count, event)) r1 = named_recorder('uno') r2 = named_recorder('dos') r1.record('zap') r2.record('zop') print r1 print r2 This code raises exceptions with both the original formulation (which wrongly repeats cls) and his suggested one (which wrongly omits *a, **k), but works as intended with the proper formulation (without repetition of cls, but WITH *a,**k) given above.