Invalid order functions

[Niklas Frykholm <niklas@...>]

If you call table.sort with an invalid sort function, you can get a call 
with (nil) to the order function before you get the "invalid order 
function" message

$ lua -e 'table.sort({1,2,3,4}, function (a,b) print(a,b) return true end)'
4       1
2       4
3       4
4       4
1       4
nil     4
lua: (command line):1: invalid order function for sorting

So usually you never see the "invalid order function" error message:

$ lua -e 'table.sort({1,2,3,4}, function (a,b) return a>0 end)'
lua: (command line):1: attempt to compare number with nil

Is this the intended behavior?

// Niklas