[Python-Dev] transitioning from % to {} formatting

[Terry Reedy]

Antoine Pitrou wrote:
> Vinay Sajip <vinay_sajip <at> yahoo.co.uk> writes:
>> Does it seems too onerous to expect people to pass an additional "use_format"
>> keyword argument with every logging call to indicate how to interpret the
>> message format string? Or does the PercentMessage/BraceMessage type approach
>> have any mileage? What do y'all think?
> 
> What about the proposal I made earlier?
> (support for giving a callable, so that you pass the "{foobar}".format method
> when you want new-style formatting)

As someone who likes .format() and who already uses such bound methods 
to print, such as in

emsg = "...".format
...
    if c: print(emsg(arg, barg))

I find this **MUCH** preferable to the ugly and seemingly unnecessary 
wrapper class idea being bandied about. This would be scarcely worse 
than passing the string itself.

Terry Jan Reedy