Feature or enhancement

There are lots of places where a new reference to a singleton is needed. This is done in a variety of ways:

1.  obj = Py_NewRef(Py_None);

2.  obj = Py_None;
    Py_INCREF(obj);

3.  Py_INCREF(Py_None);
    obj = Py_None;

4.  obj = Py_None;
    Py_INCREF(Py_None);

5.  obj = (Py_INCREF(Py_None), Py_None);

The proposal is to add another way that can hopefully become idiomatic:

6.  obj = Py_RefNone();

The following singletons are considered:

• None
• NotImplemented
• Ellipsis
• False
• True

In the internal API, helpers for the following singletons can be added:

• The strings returned by _Py_ID and _Py_STR
• The integers 0 and 1

Pitch

One advantage of using the new helpers is that it abstracts away the necessity to increment the reference count if immortal instances are implemented.

Alternatively, if immortal instances aren't implemented and all singletons are made per-interpreter, it will slightly reduce the performance overhead by making sure that the singletons are only looked up once (compared to patterns 3, 4, and 5, where the singletons are obtained twice).

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