[Python-Dev] [RFC] Removing pure Python implementation of OrderedDict

[Terry Reedy]

On 9/5/2017 2:20 PM, INADA Naoki wrote:
> On Wed, Sep 6, 2017 at 2:13 AM, Eric Snow <ericsnowcurrently at gmail.com> wrote:

>> Like Antoine, I consider the pure Python implementation to be
>> valuable.  Furthermore, the pure Python implementation is the
>> reference, so its behavior is idiomatic.

To this native English speaker, 'behavior is idiomatic' is not idiomatic 
;-).  The word 'idiomatic' refers to mode of expression, not mechanical 
behavior.  Perhaps what Eric is saying is that the behavior of the 
reference implementation is by definition correct.  Yet we have learned 
over the years to be more careful about what cpython behaviors 
constitute 'python' and which are incidental implementations. 
'Improving the test suite' sometimes mean segregating the two.

> What is *idiomatic*?
Expression that seems natural to a native speaker of a language, 
dialect, or subculture.

The question you address is which behaviors of a Python OrderedDict are 
part of the definition and which are implementation-specific, and 
whether the tests need improvement.

-- 
Terry Jan Reedy