reversing an array should preserve cyclic flag

[charlesstaats]

Current situation:

> int[] a = {1,2};
> a.cyclic = true;
> a   
0:  1
1:  2
> a.cyclic
true 
> reverse(a).cyclic
false 

It seems more consistent that if a is cyclic, then reverse(a) ought to be cyclic as well.

[charlesstaats]

Additional note: It appears that the reverse function for arrays is an undocumented convenience implemented for certain types in plain.asy, not a general function like sequence or map as I had assumed. So this is not a high priority.

[charlesstaats]

I'd even go further and observe that if you want to make reverse work the same way as it works for paths, you'd have to change the order of the elements. If you take a cyclic path with vertices a,b,c,d,e in that order and reverse it, you get a cyclic path starting in the same place with vertices a,e,d,c,b; whereas reversing an array would give you e,d,c,b,a. Changing the behavior this drastically for cyclic arrays could break things for very limited gain (given the limited nature of the reverse functions), so I'm going to close this as not feasible.

That having been said, if you want to write your own reverse function for a arrays of a given type and have it imitate the behavior of reversing a path, it could be written like this:

T[] reverse(T[] array) {
  if (array.cyclic) {
    T[] toreturn = array[-sequence(array.length)];
    toreturn.cyclic = true;
    return toreturn;
  } else {
    return array[reverse(array.length)];
  }
}