ENH,PRF: ipstruct.py: class Struct(collections.OrderedDict or dict)

[westurner]

• cross-link w/ nbformat changes, ipython/jupyter version requirements & changelog

[westurner]

• PLS ("please test")
  • TODO: enqueue a Travis build of notebook

[westurner]

See also: jupyter/nbformat#30 "ENH: v4/nbjson.py: json.loads(object_pairs_hook=collections.OrderedDict)"

[minrk]

From the README:

No functionality should be added to this repository

This package is an artifact of the Jupyter/IPython repo split, and we aren't planning to ever do another release of it, unless we find important bugs. Ultimately, we want to wean the other repos off of this one by shifting to standard utilities, such as six, etc. No new functionality should be added here. Any downstream changes that would rely on new features here should be implemented in the downstream repo instead of here.

[westurner]

No functionality should be added to this repository

I did read that.

I thought/think this solution is justifiable because:

• c "structs" are Ordered sets of keys/values.
• I have no idea what the downstream (ENH: v4/nbjson.py: json.loads(object_pairs_hook=collections.OrderedDict) jupyter/nbformat#30 interface is for nbformat.notebooknode.NotebookNode(ipython_genutils.ipstruct.Struct).
  • Would OrderedDefaultDict suffice?
  • Should there be an IStruct / INotebookNode for documentation purposes?
    • I suppose I could just run the whole [notebook, ] test grid, but a dev might have more back-history in re: what parts of Struct NotebookNode must now reimplement?

From https://mail.python.org/pipermail/python-ideas/2015-November/037163.html :

    class OrderedDefaultDict(OrderedDict):
        def __init__(self, default_factory=None, *a, **kw):
            OrderedDict.__init__(self, *a, **kw)
            self.default_factory = default_factory
        def __missing__(self, key):
            self[key] = value = default_factory()
            return value

[westurner]

Instead of DictCls as an easily-documented in-code constant, this could be:

• injectable (e.g. Struct.__init__(dictcls=collections.OrderedDict))
  • https://en.wikipedia.org/wiki/Dependency_injection
• probably mixed in (at least w/ py3)

[westurner]

See jupyter/nbformat#30 for a discussion about:

• PYTHONHASHSEED and dict.__repr__ / collections.OrderedDict.__repr__ and [doc]tests

[takluyver]

Closing along with jupyter/nbformat#30.

'Struct' is possibly an unfortunate name. The class offers some features like Structs in other languages - primarily accessing items using a.foo attribute syntax - but it already does what we need, and we don't need it to be ordered. Naming things is hard ;-)