dict-like Scope breaks locals() introspection

[mahmoud]

Hey there, long-time fan, first time filer.

The introduction of the dict-like Scope in #305 breaks a pattern I've used for a while, where the template simply echos the pprinted values of locals(). There's a test template here.

It fails with a NotImplementedError because pprint wants to use .items(). Here's a full traceback:

Traceback (most recent call last):
  File "/home/mahmoud/projects/clastic/.tox/py37/lib/python3.7/site-packages/chameleon/template.py", line 192, in render
    self._render(stream, econtext, rcontext)
  File "basic_template_78ff007bbb1662b17c111a0362aff5bd.py", line 152, in render
  File "/usr/lib/python3.7/pprint.py", line 58, in pformat
    compact=compact).pformat(object)
  File "/usr/lib/python3.7/pprint.py", line 144, in pformat
    self._format(object, sio, 0, 0, {}, 0)
  File "/usr/lib/python3.7/pprint.py", line 161, in _format
    rep = self._repr(object, context, level)
  File "/usr/lib/python3.7/pprint.py", line 393, in _repr
    self._depth, level)
  File "/usr/lib/python3.7/pprint.py", line 405, in format
    return _safe_repr(object, context, maxlevels, level)
  File "/usr/lib/python3.7/pprint.py", line 514, in _safe_repr
    vrepr, vreadable, vrecur = saferepr(v, context, maxlevels, level)
  File "/usr/lib/python3.7/pprint.py", line 511, in _safe_repr
    items = sorted(object.items(), key=_safe_tuple)
  File "/home/mahmoud/projects/clastic/.tox/py37/lib/python3.7/site-packages/chameleon/utils.py", line 427, in items
    raise NotImplementedError()
NotImplementedError

This fails on Python 3.7-3.9 at least, and chameleon==3.10 through master. (lines in question)

I'm hoping this acts as motivation to implement items(), assuming it's not prohibitively complex.

Thanks again!

[malthe]

@mahmoud how does that work for you?

[mahmoud]

Hey, thanks for getting to this so quickly. Just checked the branch against my little set of tests and it's all green on this end. Thanks!