[Python-ideas] a sorting protocol dunder method?

[Rhodri James]

On 04/12/17 18:01, brent bejot wrote:
> I'm +1 on this idea for the most part.
> 
> I agree particularly with the idea that it is better OOP for an object to
> access it's member variables to create the key than an external container
> to do so.

This I'm absolutely fine with.  Key methods are something to encourage. 
The problem that I have is that once you get beyond simple lists of 
number or strings, there often isn't a particularly obvious sort order, 
or rather there are often multiple obvious sort orders and you may want 
any of them.  In fact I'd go so far as to suggest that there _usually_ 
isn't a single obvious sort order for non-trivial classes.

To take a non-Python example, I'm in charge of the reading rota at my 
local church, and I keep a spreadsheet of readers to help me.  Usually I 
sort that list by the date people last read the lesson, so I can quickly 
tell who I should ask next.  When the newsletter asks me for a list of 
readers, though, I sort them alphabetically by surname, which most 
people would think of as the natural sorting order.

-- 
Rhodri James *-* Kynesim Ltd