[Python-Dev] Keeping interned strings in a set

[Alexander Belopolsky]

As an exercise in using the new set C API, I've replaced the
"interned" dictionary in stringobject.c with a set.  Surprisingly,
what I thought would be a simple exercise, took several hours to
implement and debug.  Two problems are worth mentioning:

1. I had to add a function to setobject.h to retrieve a pointer to an
object stored in a set. I could not find a way to do it using current
API (short of iterating through the set of course).

2. I had to change the  PyString_Fini() and PySet_Fini() in
Py_Finalize() because cleaning "interned" set cannot be done after the
set module is finalized.

If there is any interest, I will submit a patch, but it does not seem
to affect performance in any meaningful way.