In my experience it usual means that you need some form of time reversal e.g. unsend an email or put a BEGIN TRAN before the SQL you just executed.

Reasonably sure that can't be done in C even with all that undefined behaviour.

However, if your IO monad implementation is sufficiently slow, you could ^C between when you thought the code had executed and when it actually bothered to get around to it.

I can't believe that none of the functional ninjas thought to add time travel as a benefit. Most remiss...

> I can't believe that none of the functional ninjas thought to add time travel as a benefit. Most remiss...

Ahem: https://hackage.haskell.org/package/tardis

With much delight, I stand corrected.

Haskell perpetually astonishes me. Not only is it, more or less single-handedly, keeping the Holy Wars alive, it now appears to supply punchlines to jokes. Amazing.

Wouldn't you do the same if you had a time machine?