Bye,
bearophile
Believe me I just don't post on here without first trying to
answer the question on my own.
I was already on the std.algorithm and found this:
Swaps lhs and rhs. The instances lhs and rhs are moved in memory,
without ever calling opAssign, nor any other function. T need not
be assignable at all to be swapped.
If lhs and rhs reference the same instance, then nothing is done.
lhs and rhs must be mutable. If T is a struct or union, then its
fields must also all be (recursivelly) mutable.
now say A[] was = [90, 50, 33, 72, 35]
and by the end of the function B[] = [33, 50, 72, 90, 35]
now we call swap(A,B) and A would now = [33, 35, 50, 72, 90]
and somehow the 35 moves in front of the 50.
