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The type is available as types.SimpleNamespace, and there's no reason to hold PyNamespace_New() back.

SimpleNamespaces also need to be picklable.

Patch to make PyNamespace_New() public.

I'll get a patch up tomorrow to make the type pickleable.

I'll get to a pickle patch as soon as I can. I also need to add a doc addition for PyNamespace_New() to the existing patch.

It would be nice to have a minimum documentation :-) What is the kwds parameter? What are attributes of the object?

Where should the docs go for PyNamespace_New()? I looked at what's in Doc/c-api/concrete.rst (concrete.html#other-objects), and each of them points to its own page. Adding a new page for a single function seems a bit too much. :) Would it be bad to put the doc right at the end of concrete.rst? The attached patch does so.
(Also just noticed that PyStructSequence_* is not documented...)

I've opened issue 15022 for making SimpleNamespace picklable.

> The type is available as types.SimpleNamespace
(sorry for being OT) Is this documented in whatsnew? Also, I remember a discussion about making it public or not, but don’t recall a decision. I personally find it bad that we have structseqs for most things, dicts in PEP 418 get_clock_info return values, and now simplenamespace for sys.implementation.

> Is this documented in whatsnew?
I'm not sure what has been (none of my patches have done so).
> Also, I remember a discussion about making it public or not, but
> don’t recall a decision.
Amaury brought it up in msg162127. His point was that the type is public in Python, so why not the C API? That's about the extent of the discussion. :) Do you see any harm in making PyNamespace_New() public?
> I personally find it bad that we have structseqs for most things, dicts
> in PEP 418 get_clock_info return values, and now simplenamespace for
> sys.implementation.
The use cases are different for the different types. StructSequence/namedtuple provides fixed data structures for structured records. A dict is essentially the opposite: an un-fixed data structure for dynamic namespaces, making no firm promises as to what the future holds.
SimpleNamespace fills a similar role to dicts, but offers a higher appearance of stability by virtue of using attributes vs. keys. The problem is that moving from item-access to attribute-access is not a backward-compatible change. That's the big reason why PEP 421 specified the use of an attr-based object.

>> Is this documented in whatsnew?
> I'm not sure what has been (none of my patches have done so).
Okay; if a committer does not add a note we can open a doc bug to not forget that.
>> Also, I remember a discussion about making it public or not, but
>> don’t recall a decision.
> Amaury brought it up in msg162127. His point was that the type is public in Python, so why not the C API?
Actually I was talking about making it public at all, i.e. in Python too.
> The use cases are different for the different types. StructSequence/namedtuple provides fixed data structures
> for structured records. A dict is essentially the opposite: an un-fixed data structure for dynamic namespaces,
> making no firm promises as to what the future holds.
Right; I just don’t see why the clock info needs to be a dict instead of a structseq or simplenamespace, but maybe it’s explained in the PEP and I missed it. Also it seems to me that the only advantage of simplenamespace over structseqs is that it has no order and can’t be unpacked; I don’t find that a very strong argument (I do see its value, e.g. "major, minor, *etc = sys.version_info" makes sense but we really don’t want to assign order to sys.implementation elements), but I guess this ship has sailed when the implementation was approved.

Here's an updated patch to address the use of _PyNamespace_New() in changeset 77414:0011536f2a06.

-1. The entire Python API is already accessible from C, so expansions to the public C API need more justification than "it's exposed in Python".
If new instances of this type end up being used in performance critical third party C extensions, then we can have a conversation about whether or not it needs to be exposed directly in C.

-1 for the reasons Nick stated.

Suggest closing or marking "remind" and see if people use / request / reimplement SimpleNamespace.

At present, I don't see a need to make the C API public.