Wouldn't a composite subroutine be more efficient?

Generally, evaling at runtime is quite expensive. You'd have to benchmark to say for sure. I guess it depends upon how many time your going to call the composite sub. If your processing large datasets, the cost of eval may become insignificant.

I usally avoid evaling stuff input from the command line, though ]broquaint]'s use of package->can() seems to avoid most of the risks that usually entails. I liked his solution a lot.

Yes, I screwed up the order. reverse is the easiest solution.