Regarding catch/throw, I don’t believe any current CL implementation could optimise this but: - if the prints were changed to go outside of the catches before

Regarding catch/throw, I don’t believe any current CL implementation could optimise this but: - if the prints were changed to go outside of the catches before executing (ie so the compiler could know that they wouldn’t throw) then I think a sufficiently smart compiler could prove that nothing else could throw here (it would be allowed to know that elt wouldn’t throw) - If I recall correctly, there are java compilers which can optimize throw-inside-catch code to not need the catch on the control stack. (Ie the throw is just compiled into a goto) - some languages allow one to throw things that are unique to the function call which gives a better chance of them being unique.