DB<50> sub tst { "a".."d" }

  DB<51> x tst()              # list context   => range
0  'a'
1  'b'
2  'c'
3  'd'
  DB<52> p scalar tst()       # scalar context => flip-flop 
1E0
  DB<53> x tst()              # list context   => WTF???
0  0
  DB<54> x tst()              # once flip-flop, always flip-flop
0  0
  DB<55>