$ perl -le " use v5.10; sub f {  state $f = $_[0]; warn qq{ $f # @_ }; $f; } f({},$_) for 1 .. 4  "
 HASH(0x3f9b34) # HASH(0x3f9b34) 1  at -e line 1.
 HASH(0x3f9b34) # HASH(0x3f9b44) 2  at -e line 1.
 HASH(0x3f9b34) # HASH(0x3f9b94) 3  at -e line 1.
 HASH(0x3f9b34) # HASH(0x3f9b44) 4  at -e line 1.