Re: [Python-Dev] PEP 310 and exceptions

2005-04-23 Thread Nick Coghlan
Shane Hathaway wrote: Nick Coghlan wrote: Which means finding a different name for '__else__'. Two possibilities that occur to me are '__ok__' or '__no_except__'. The latter makes a fair amount of sense, since I can't think of a way to refer to the thing other than as a 'no exception' handler. Wh

Re: [Python-Dev] PEP 310 and exceptions

2005-04-23 Thread Shane Hathaway
Nick Coghlan wrote: > Which means finding a different name for '__else__'. Two possibilities > that occur to me are '__ok__' or '__no_except__'. The latter makes a > fair amount of sense, since I can't think of a way to refer to the thing > other than as a 'no exception' handler. While we're on th

[Python-Dev] Re: __except__ use cases

2005-04-23 Thread Nick Coghlan
holger krekel wrote: On a side note, I don't see too much point in having __except__ return something when it is otherwise easy to say: def __except__(self, typ, val, tb): self.abort_transaction() raise typ, val, tb It has to do with "Errors should never pass silently, unl

Re: [Python-Dev] PEP 310 and exceptions

2005-04-23 Thread Nick Coghlan
Aahz wrote: On Sat, Apr 23, 2005, Nick Coghlan wrote: In light of Alex's comments, I'd actually like to suggest the below as a potential new definition for PEP 310 (making __exit__ optional, and adding an __else__ handler): if hasattr(x, '__enter__'): x.__enter__() try: try:

Re: [Python-Dev] PEP 310 and exceptions

2005-04-23 Thread Nick Coghlan
Bernhard Herzog wrote: With the proposed implementation of PEP 310 rev. 1.5 it wouldn't work. sys.exc_info returns a tuple of Nones unless an except: clause has been entered. Either sys.exc_info() would have to be changed to always return exception information after an exception has been raised or

Re: [Python-Dev] PEP 310 and exceptions

2005-04-23 Thread Bernhard Herzog
Nick Coghlan <[EMAIL PROTECTED]> writes: > holger krekel wrote: >> Moreover, i think that there are more than the "transactional" >> use cases mentioned in the PEP. For example, a handler may want to >> log exceptions to some tracing utility or it may want to swallow >> certain exceptions when >>

Re: [Python-Dev] PEP 310 and exceptions

2005-04-23 Thread Phillip J. Eby
At 01:41 PM 4/23/05 +1000, Nick Coghlan wrote: Whichever way that point goes, this definition would allow PEP 310 to handle Alex's example of factoring out standardised exception handling, as well as the original use case of resource cleanup, and the transaction handling: class transaction(obje

__except__ use cases (was: Re: [Python-Dev] PEP 310 and exceptions)

2005-04-23 Thread holger krekel
On Sat, Apr 23, 2005 at 13:41 +1000, Nick Coghlan wrote: > Nick Coghlan wrote: > In light of Alex's comments, I'd actually like to suggest the below as a > potential new definition for PEP 310 (making __exit__ optional, and adding > an __else__ handler): > > if hasattr(x, '__enter__'): >

Re: [Python-Dev] PEP 310 and exceptions

2005-04-23 Thread Aahz
On Sat, Apr 23, 2005, Nick Coghlan wrote: > > In light of Alex's comments, I'd actually like to suggest the below as a > potential new definition for PEP 310 (making __exit__ optional, and adding > an __else__ handler): > > if hasattr(x, '__enter__'): > x.__enter__() > try: >

Re: [Python-Dev] PEP 310 and exceptions

2005-04-23 Thread holger krekel
On Fri, Apr 22, 2005 at 19:03 -0700, Josiah Carlson wrote: > [EMAIL PROTECTED] (holger krekel) wrote: > > basically translates to: > > > > if hasattr(x, '__enter__'): > > x.__enter__() > > try: > > ... > > except: > > if hasattr(x, '__except__'): x.__excep

Re: [Python-Dev] Error checking in init functions

2005-04-23 Thread Michael Hudson
Thomas Heller <[EMAIL PROTECTED]> writes: > I always wondered why there usually is very sloppy error checking in > init functions. Laziness, I presume... > The problem is that when one of these things fail (although they are > probably supposed to NOT fail) you end up with a module missing > som

Re: [Python-Dev] Proper place to put extra args for building

2005-04-23 Thread Martin v. Löwis
Brett C. wrote: >>You means sysconfig.py, right? Right. > No, I mean Python's setup.py; line 174. Ah, ok. > You mean Distutils' sysconfig, right? I can change that as well if you want. Please do; otherwise, people might see strange effects. Regards, Martin ___

RE: [Python-Dev] Caching objects in memory

2005-04-23 Thread Raymond Hettinger
[Facundo Batista] > Is there a document that details which objects are cached in memory > (to not create the same object multiple times, for performance)? The caches get cleaned-up before Python exit's, so you can find them all listed together in the code in Python/pythonrun.c: /* Sundry

Re: [Python-Dev] anonymous blocks

2005-04-23 Thread Timothy Fitz
On 4/21/05, Guido van Rossum <[EMAIL PROTECTED]> wrote: >for dummy in synchronized(the_lock): >BODY > > or perhaps even (making "for VAR" optional in the for-loop syntax) > with > >in synchronized(the_lock): >BODY > > Then synchronized() could be written cleanly as follo

[Python-Dev] Error checking in init functions

2005-04-23 Thread Thomas Heller
I always wondered why there usually is very sloppy error checking in init functions. Usually it goes like this (I removed declarations and some other lines for clarity): PyMODINIT_FUNC PyInit_zlib(void) { m = Py_InitModule4("zlib", zlib_methods, zlib_module_documentatio

Re: [Python-Dev] anonymous blocks

2005-04-23 Thread Shane Hathaway
Nick Coghlan wrote: > An alternative would be to replace the 'yield None' with a 'break' or > 'continue', and create an object which supports the resource protocol > and NOT the iterator protocol. Something like: > > def my_resource(): > print "Hi!" # Do entrance code > continue # Go on

[Python-Dev] Re: anonymous blocks

2005-04-23 Thread Reinhold Birkenfeld
Nick Coghlan wrote: > Interestingly, with this approach, "for dummy in my_resource()" would still > wrap > the block of code in the entrance/exit code (because my_resource *is* a > generator), but it wouldn't get the try/finally semantics. > > An alternative would be to replace the 'yield None

Re: [Python-Dev] anonymous blocks

2005-04-23 Thread Nick Coghlan
Shane Hathaway wrote: There's a lot of boilerplate code there. Using your suggestion, I could write that something like this: def transaction(): begin_transaction() try: continue except: abort_transaction() raise else: