$r = () ;                  # Case 1 -- $r -> undef
  $r = 1234 ;                # Case 2 -- $r -> 1234
  $r = (12, 23, 34, 45) ;    # Case 3 -- $r -> 45
  $r = 'a'..'z' ;            # Case 4 -- error
  $s = ('a'..'z')[4..15] ;   # Case 5 -- $r -> 'p'
  $t = @r[7..16] ;           # Case 6 -- $r -> 'q'
  $u = $r[@q] ;              # Case 7 -- $r -> 'n'
  $w = @r{'k'..'p'} ;        # Case 8 -- $w -> 16
  $w = @r{@p} ;              # Case 9 -- $w -> 16