[Python-ideas] PEP 428 - object-oriented filesystem paths
steve at pearwood.info
Sun Oct 7 06:33:42 CEST 2012
On 06/10/12 09:54, Andrew McNabb wrote:
> On Sat, Oct 06, 2012 at 08:41:05AM +1000, Steven D'Aprano wrote:
>> On 06/10/12 05:53, Andrew McNabb wrote:
>>> Path concatenation is obviously not a form of division, so it makes
>>> little sense to use the division operator for this purpose.
>> But / is not just a division operator. It is also used for:
>> * alternatives: "tea and/or coffee, breakfast/lunch/dinner"
>> * italic markup: "some apps use /slashes/ for italics"
>> * instead of line breaks when quoting poetry
>> * abbreviations such as n/a b/w c/o and even w/ (not applicable,
>> between, care of, with)
>> * date separator
> This is the difference between C++ style operators, where the only thing
> that matters is what the operator symbol looks like, and Python style
> operators, where an operator symbol is just syntactic sugar. In Python,
> the "/" is synonymous with `operator.div` and is defined in terms of the
> `__div__` special method. This distinction is why I hate operator
> overloading in C++ but like it in Python.
I'm afraid that it's a distinction that seems meaningless to me.
int + int and str + str are not the same, even though the operator symbol
looks the same. Likewise int - int and set - set are not the same even
though they use the same operator symbol. Similarly for & and | operators.
For what it is worth, when I am writing pseudocode on paper, just playing
around with ideas, I often use / to join path components:
open(path/name) # pseudo-code
sort of thing, so I would be much more comfortable writing either of these:
which looks like it ought to be a lookup, not a constructor.
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