[Python-Dev] PEP 414 - Unicode Literals for Python 3

[Vinay Sajip]

 <martin <at> v.loewis.de> writes:

> 
> > A couple of people have said that 'native string' is spelt 'str', but I'm not
> > sure that's the right answer. For example, 2.x's cString.StringIO  
> > expects native strings, not Unicode:
> 
> Your counter-example is non-ASCII characters/bytes. I doubt that this  
> is a valid
> use case; in a "native" string, these shouldn't occur (i.e. native  
> strings should
> always be ASCII), since the semantics of non-ASCII changes drastically between
> 2.x and 3.x. So whoever defines some API to take "native" strings  
> can't have defined
> a valid use of non-ASCII in that interface.

It might not be a valid usage, but the 2.x ecosystem has numerous occurrences of
invalid usages, which tend to crop up when porting because of 3.x's increased
strictness.

In the example I gave, cStringIO.StringIO should be able to cope with text
strings, but doesn't. Of course there are StringIO.StringIO and io.StringIO in
2.6, but when porting a project, you can't be sure which of these you might run
into.

> Indeed it should. If there is a known application of non-ASCII native strings,
> I surely would like to know what that is.

I can't think of a specific instance off-hand, but I seem to recall having
problems with some of the cookie APIs insisting on native strings (rather than
text, which is validated against ASCII where appropriate).

Regards,

Vinay Sajip