On Tue, Sep 29, 2009 at 8:15 PM, "Martin v. Löwis" <mar...@v.loewis.de> wrote:
> Steven Bethard wrote:
>> Consider an example from the logging
>> docs:
>>
>> logging.Formatter("%(asctime)s - %(name)s - %(levelname)s - %(message)s")
>>
>> We'd like to support both this style as well as the following style:
>>
>> logging.Formatter()
>
> Now, that's different. IIUC, you are not actually performing the
> substitution here, but only at a later place.
>
> So changing to the new formatting mechanism is an API change.
> I agree that the new placeholder syntax needs to be supported.Just to be clear, I don't think logging is the only place these kind of things happen. Some others I found looking around: BaseHTTPServer.BaseHTTPRequestHandler.error_message_format http://docs.python.org/library/basehttpserver.html#BaseHTTPServer.BaseHTTPRequestHandler.error_message_format BaseHTTPServer.BaseHTTPRequestHandler.log_message http://docs.python.org/3.1/library/http.server.html#http.server.BaseHTTPRequestHandler.log_message email.generator.DecodedGenerator http://docs.python.org/library/email.generator.html#email.generator.DecodedGenerator There may be more. > I would propose that the format argument gets an argument name, > according to the syntax it is written in. For PEP 3101 format, > I would call the argument "format" (like the method name of the > string type), i.e. > > logging.Formatter( > format="{asctime} - {name} - {levelname} - {message}") > > For the % formatting, I suggest "dicttemplate" (assuming that > you *have* to use dictionary %(key)s style currently). > > The positional parameter would also mean dicttemplate, and > would be deprecated (eventually requiring a keyword-only > parameter). This is a nice solution for the cases where we can be confident that the parameter is currently only used positionally. However, at least in Python 3.1, "fmt" is already documented as a keyword parameter: http://docs.python.org/3.1/library/logging.html#logging.Formatter I guess we could follow the same approach though, and have fmt= be the %-style formatting, and use some other keyword argument for {}-style formatting. We've got a similar problem for the BaseHTTPRequestHandler.error_message_format attribute. I guess we'd want to introduce some other attribute which is the error message format for the {}-style formatting? Steve -- Where did you get that preposterous hypothesis? Did Steve tell you that? --- The Hiphopopotamus _______________________________________________ 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
