Guido van Rossum wrote:
> I just read Raymond Chen's rant against control flow macros:
> http://blogs.msdn.com/oldnewthing/archive/2005/01/06/347666.aspx
>
> I think this pretty much kills PEP 340, as well as Nick Coghlan's
> alternative: both proposals let you write a "template" that can be
> used to hide exception-catching code, which is a form of control flow
> (and a pretty important one if you read Chen's rant against exceptions
> referenced by the former, even if you don't agree with everything he
> says in the latter).
It seems the effect of Raymond's articles on you was similar to their effect on
me :)
> Straight up-or-down votes in the full senate are appreciated at this point.
PEP 340 redux for me (as you might have guessed) - I think the transaction()
use
case is a genuinely useful one. The ability to access the return value of
__enter__() is also more useful than simply duplicating what could be achieved
by an assignment on the line before the user defined statement.
> On to the secondary questions:
>
> - Today I like the 'do' keyword better; 'with' might confuse folks
> coming from Pascal or VB
I think 'do' can be made to read correctly in more contexts that 'with'. The
lack of a corresponding 'while' or 'until' should eliminate any temptation to
see it as a loop.
The 'with' keyword also means I keep wanting the magic methods to be called
"__acquire__" and "__release__" (and those would be harder to type. . .)
> - I have a more elaborate proposal for __exit__'s arguments. Let the
> translation be as follows:
I plan to rewrite my proposal based on this suggestion, just to explore the
ramifications. I think it will turn out quite nicely.
The ban on yielding inside try/finally will need to be extended to yielding
inside user defined statements until such time as an iterator finalisation
protocol is chosen, though.
> (An alternative would be to always call it with 4 arguments, the last
> three being None in the first two cases.)
The former is probably tidier. __exit__() method implementations which don't
care about the exception details can still use "*exc_info" in the argument
signature, while those that want to use the information can just name the three
parts without needing to specify the "=None" defaults.
Cheers,
Nick.
--
Nick Coghlan | [EMAIL PROTECTED] | Brisbane, Australia
---------------------------------------------------------------
http://boredomandlaziness.blogspot.com
_______________________________________________
Python-Dev mailing list
Python-Dev@python.org
http://mail.python.org/mailman/listinfo/python-dev
Unsubscribe:
http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
