Q: sort's key and cmp parameters

[Paul Rubin]

Duncan Booth <duncan.booth at invalid.invalid> writes:
> > Is there a real-life sorting task that requires (or is far more
> > efficient with) cmp and can't be easily achieved with key and reverse?
> > 
> There is no sorting task that *requires* cmp. If all else fails you can 
> define a key class to wrap the original wrapper such that comparing the 
> keys simply calls the comparison function that you *would* have used.

I would count that as key being far less efficient, though still
giving the same result.