it makes no sense. It is wrong.

As to see what makes sense:
scalar(@ra)   counts the elements of array @ra.
while ( scalar( @ra ) )   does a while condition around the counting. In this case, you would normally just leave out the counting and write   while ( @ra )
Anyway, there needs to be a { } block as to which the while condition belongs. It is missing, that's an error I can't make any sense of.

Sören