> On 2 Oct 2019, at 09:14, DL Neil via Python-list <python-list@python.org>
> wrote:
>
> On 2/10/19 12:52 AM, Rhodri James wrote:
>> On 01/10/2019 06:03, DL Neil via Python-list wrote:
>>> On 30/09/19 9:28 PM, Barry Scott wrote:
>>>>> On 30 Sep 2019, at 05:40, DL Neil via Python-list
>>>>> <python-list@python.org> wrote:
>>>>>
>>>>> Should pathlib reflect changes it has made to the file-system?
>>>>
>>>> I think it should not.
>>>
>>> The term "concrete" is applied to Path(), PosixPath(), and WindowsPath() -
>>> whereas the others are differentiated with the prefix "Pure".
>>>
>>> I take "concrete" to mean 'existing in reality or real experience'. Thus, I
>>> saw the Pure* entities as supporting abstract paths, but the concrete
>>> entities as representing (and reflecting) real-world (file system) entities.
>>>
>>> Thus, there is no need for .exists() to be available in the Pure paths, but
>>> there is when utilising their concrete implementations.
>> Sorry but your logic is inconsistent here. For starters, it's not that
>> there's no need for .exists() in Pure paths, it's that .exists() is
>> meaningless. Pure paths aren't related to any actual filing system (to
>> paraphrase you), so existence isn't an option.
>> However if you insist that "concrete" means "existing in reality", then
>> .exists() is unnecessary because by your very definition the path must
>> exist. The very act of creating the Path object would create the
>> corresponding file or directory. So either pathlib does something horrific,
>> or your definition is wrong.
>
>
> Very good! Yes, I'd picked-on .exists() purely (hah!) because it does not
> appear in PurePaths, but does in concrete Paths.
>
> On which topic, I went looking for a decent technical definition of the word,
> but instead of coming-out smiling, I've been left somewhat stony-faced (hah,
> hah!).
"concrete
adj.
Of or relating to an actual, specific thing or instance; particular.
"
> That said, it is one of the ways that a path can be shown to transition from
> some 'pure' state to become 'concrete'.
>
> However, A.N.Other has suggested that I might be mis-applying the word
> "concrete", so maybe not.
Concrete means a specific operating system's filesystem rules, Windows or Posix.
>
> A definition/description would be useful. Any pointers?
Barry
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