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

Vinay Sajip vinay_sajip at yahoo.co.uk
Thu Oct 1 15:29:29 CEST 2009

Paul Moore <p.f.moore gmail.com> writes:

This seems to me to be almost the same as the previous suggestion of having a string subclass:

class BraceFormatter(str): def mod(self, other): # Needs more magic here to cope with dict argument return self.format(*other) __ = BraceFormatter_ logger.debug(("The {0} is {1}"), "answer", 42)_ The only real differences are 1. The positioning of the closing parenthesis 2. The internal implementation of logger.debug needs to preserve string subclasses properly

The other difference is that my suggestion supports Barry's desire to use string.Template with no muss, no fuss ;-) Plus, very little additional work is required compared to your items 1 and 2. ISTM BraceMessage would be something like this,

clsss BraceMessage: def init(self, fmt, *args, **kwargs): self.fmt = fmt self.args = args self.kwargs = kwargs

def __str__(self):
    return self.fmt.format(*self.args, **self.kwargs)

Regards,

Vinay

More information about the Python-Dev mailing list