[winstonewert]

I suppose it would make more sense to write these as lambdas in a c style syntax

   nums.map(|sublist| sublist.map(|num| add(num, 5))

Maybe I haven't done enough functional programming yet, but I still like the explicitness of the C-style over the functional style.

[kasbah]

Sorry, but there is nothing more explicit about using lambdas as you have done, it's simply redundant (notice the repetition of sublist and num arguments).