[Python-Dev] frozenset C API?

[Bill Janssen]

I'm working on issue 1583946.  Nagle pointed out that each DN (the
"subject" and "issuer" fields in a certificate) may have multiple
values for the same attribute name, and I haven't been able to rule
this out yet.  X.509 DNs are sets of X.500 attributes, and X.500
attributes may be either single-valued or multiple-valued.  I haven't
found anything in the X.509 standard that prohibits multiple-valued
attributes (yet -- I'm still looking), so I'm working on an
alternative to using dicts to represent the set of attributes in the
certificate that's returned from ssl.sslsocket.getpeercert().
"frozenset" seems the most appropriate -- it's a non-ordered immutable
set of attributes.  Could use a tuple, but (1) that implies order,
and (2) using set operations on the attribute set would be handy to
test for various things, particularly "issubset" and "issuperset".

I think frozenset is quite analogous to tuple at this level, and I
suggest that a similar set of C construction functions would be a good
thing.

Bill

> I guess nobody has tried to create frozenset instances from C code
> before. Almost everyone uses set anyway. What are you trying to do?
> 
> On 9/4/07, Bill Janssen <janssen at parc.com> wrote:
> > I'm looking at building a "frozenset" instance as a return value from
> > a C function, and the C API seems ridiculously clumsy.  Maybe I'm
> > misunderstanding it.  Apparently, I need to create a list object, then
> > pass that to PyFrozenSet_New(), then decref the list object.
> >
> > Is that correct?
> >
> > What I'd like is something more like
> >
> >      PyFrozenSet_NEW(int) => PySetObject *
> >      PyFrozenSet_SET_ITEM(s, i, v)
> >
> > Any idea why these aren't part of the API?
> >
> > Bill
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> 
> 
> -- 
> --Guido van Rossum (home page: http://www.python.org/~guido/)