Sorting according to a primary and secondary criterion

[bearophile]

Joseph Rushton Wakeling:

>     idx.sort!("arr1[a] < arr1[b] || (arr1[a] == arr1[b] && 
> arr2[a] < arr2[b])");
>
> I (unsurprisingly) get a load of errors about std.functional 
> not having access to arr1 or arr2.

You need a lambda delegate for that. But I forgot about multisort 
algorithm... It's probably the right tool.

Bye,
bearophile