[Python-Dev] PEP 461: Adding % formatting to bytes and bytearray -- Final, Take 3

[Guido van Rossum]

On Thu, Mar 27, 2014 at 11:52 AM, Daniel Holth <dholth at gmail.com> wrote:

> I feel not including %s is nuts. Should I write .replace('%b', '%s')?
>

I assume you meant .replace('%s', '%b') (unless you're converting Python 3
code to Python 2, which would mean you really are nuts :-).

But that's not going to help for the majority of code using %s -- as I am
trying to argue, %s doesn't mean "expect the argument to be a str" and
neither is that how it's commonly used (although it's *possible* that that
is how *you* use it exclusively -- that doesn't make you nuts, just more
strict than most people).


> All I desperately need are APIs that provide enough unicode / str type
> safety that I get an exception when mixing them accidentally... in my
> own code, dynamic typing is usually a bug. As has been endlessly
> discussed, %s for bytes is a bit like exposing sprintf()...
>

I don't understand that last claim (I can't figure out whether in this
context is exposing sprintf() is considered good or bad). But apart from
that, can you give some specific examples?

PS. I am not trying to be difficult. I honestly don't understand the use
case yet, and the PEP doesn't do much to support it.

-- 
--Guido van Rossum (python.org/~guido)
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