[Python-Dev] transitioning from % to {} formatting (original) (raw)

Terry Reedy tjreedy at udel.edu
Fri Oct 2 07:49:34 CEST 2009

Antoine Pitrou wrote:

Vinay Sajip <vinaysajip yahoo.co.uk> writes:

Does it seems too onerous to expect people to pass an additional "useformat" 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

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