2010/7/25 Ivan Pozdeev <vano@mail.mipt.ru>:
Здравствуйте, Nick.
Вы писали 24 июля 2010 г., 14:12:31:
Why is that a problem? Some errnos *are* more important than others - they're the ones the regularly appear on the right hand side of "errno == <some_errno>" checks.
Why would you consider new classes that would be based on a survey of the errnos that developers actually check for in published code to be "arbitrary"?
Since the list would be a sole opinion of some people who take part in the survey, you'll be constantly faced with demands of other people who want to have "shortcuts" for something else too. And you won't be able to explain why your choice is more preferable than theirs.
As Alexander pointed out, the word survey has multiple meanings. One of those is the subjective approach you're objecting to (ask a bunch of people what they think), another is the more objective approach actually documented in the PEP (go and look at what is out there, as in the sense of "land survey"). Think "code survey" rather than "developer survey". (A scripted tool to gather statistics on exception handling in this space from Google code search results and direct scans of local Python code bases would actually be helpful, even if it wasn't 100% accurate) There is still a subjective step in whittling the code survey results down into a revised class heirarchy, but that's: - why it's a separate step in the PEP, independent of the consolidation step - why the PEP doesn't include a concrete proposal as yet - one of the main goals of discussion of the PEP here and across the wider Python community Language design is inherently a matter of judgment. Based on the way it has played out in practice (frequently requiring explicit errno checks and catching of multiple exception types in order to write correct code), we now think the previous judgment in relation to the EnvironmentError exception hierarchy is demonstrably flawed. That doesn't mean we throw our hands up in the air and give up - it means we knuckle down and try to come up with something better, based on what we can learn from what has gone before. Cheers, Nick. -- Nick Coghlan | ncoghlan@gmail.com | Brisbane, Australia