Nice, though I'm used to shift meaning "remove the first value of the
(resizable) array and return the value", I think your proc feels more like it's
"scrolling" the array?
Anyway, naming aside, what do you think of this version?
proc scroll[T](a: var openarray[T]; d: int) =
if d == 0: discard # do nothing
elif abs(d) >= a.len: # reset all
for el in a.mitems: el.reset
elif d > 0: # right shift
for i in countdown(a.len-1,d):
a[i]=a[i-d]
for j in 0..<d: a[j].reset
elif d < 0: # left shift
for i in -d..<a.len:
a[i+d]=a[i]
for j in countdown(-d,1): a[^j].reset
