[Python-Dev] PEP 460 reboot (original) (raw)

Antoine Pitrou solipsis at pitrou.net
Tue Jan 14 20:23:03 CET 2014

On Tue, 14 Jan 2014 10:52:05 -0800 Guido van Rossum <guido at python.org> wrote:

Would you rather raise an exception, truncate the value, or mess up the formatting? All languages newer than Fortran that I've used have chosen the latter, and I still agree it's a good idea.

Well that's useful when printing out human-readable stuff on stdout, much less when you're emitting binary data that's supposed to conform to a well-defined protocol. I expect bytes formatting to be used for the latter, not the former.

(which also means, actually, that I don't think the fancy formatting features - alignment, etc. - are useful at all for bytes; but it's probably ok having them for consistency)

Similar with infinities, NaN, or None. (Yes, it's embarrassing to have a website displaying 'null'. But isn't a 500 even more embarrassing?)

When it comes to type mismatch, though, an error is raised:

"%d" % object() Traceback (most recent call last): File "", line 1, in TypeError: %d format: a number is required, not object

(instead of outputting e.g. repr(id(x)))

Regards

Antoine.

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