[Python-3000] Support for PEP 3131

[Stephen J. Turnbull]

Ka-Ping Yee writes:

 > On Tue, 12 Jun 2007, Stephen J. Turnbull wrote:
 > > It seems to me that rather than *impose* restrictions on third
 > > parties, the sensible thing to do is to provide those restrictions to
 > > those who want them.
 > 
 > Hang on a second.  No one is *imposing* new restrictions.  Python
 > uses ASCII-only identifiers today and has always been that way.

Who said "new"?  PEP 3131 is approved, so "reimpose", if you like.
But I don't want it, and definitely consider it an imposition, and
have done so since the discussion of PEP 263.

 > The big missing concern from your list is that the vast majority
 > won't *know* that the character set is changing on them, so they
 > won't know that they need to do any of these things.

Deliberate omission.

Such restrictions seem unacceptable to both Guido and Martin; the
*only* point of this proposal is to see if there's a way we can
achieve Jim's goal of no change to his best current practice without a
global setting unacceptable to Guido.

If you want to use this technology to change the default, fine, but
it's not part of my proposal.

 > > 1.  PEP 263 codecs delegate the decision to the code's author;
 > 
 > I'd be okay with this if [...]

[I'm not sure what you mean; I've deliberately edited to show the
meaning I took.]

I'm not OK with it.  Auditing by definition is under control of the
user, not the source code.  I don't see a real point in doing this if
the user or site can't enforce auditing, since they *can* do so by
explicitly running an external utility.

 > > 2.  The auditor would have to duplicate the work of the parser, and
 > >     might get it wrong.
 > > 3.  Parsing is expensive in time and other resources.
 > 
 > Both of these come down to the wastefulness of redoing something
 > that the Python interpreter itself already knows how to do very
 > well, and is, in some sense by definition, the authority on how
 > to do it correctly.

True.  However, Guido has already indicated that he favors some
approach like this, as an external lint utility.  My question is how
to minimize impact on users who desire flexible automatic auditing.