Sorting according to a primary and secondary criterion

[bearophile]

Joseph Rushton Wakeling:

> Actually, I don't find it needs any more memory than regular 
> schwartzSort (which I was using anyway),

A and array of tuples should take more memory. Try with a much 
larger input array.


> but it does cost _speed_ -- quite a lot. :-(

Right, schwartzSort is quite slow:
http://d.puremagic.com/issues/show_bug.cgi?id=5077

But thankfully there are simple means to speed up schwartzSort... 
(like using alloca for small input arrays, improving its code, 
using minimallyInitializedArray, etc).

Bye,
bearophile