The docs on the 'sort' function says "Sorts lst by destructively
exchanging its elements." From this I get the impression that
(let L (3 2 5 4) (sort L) L)
should give the same result as
(let L (3 2 5 4) (sort L))
but that's not so, as the first one reveals that L get the value
(3 4 5), while the (more expected) value returned by the (sort L) itself
was (2 3 4 5). Why couldn't L simply be given the same value?