[anardil]

It definitely has some sharp edges. One advantage is skipping computations (and the IO they'd need) that don't end up getting used, which let's you do some clever looking things/ ignore some details. That's hard to take advantage of in practice, I think.

The other advantage is just deferring IO. For instance in split or tee, you could decide that you need 500 output files and open all the handles together in order to pass them to another function that will consume them. I'd squint at someone who wrote `void process_fds(int fds[500]);`, but here it doesn't matter.