my ($this, $that, $other) = split (/\s+/, $line); 
# $line might have < 3 elements in it, the rest will be undef

##</code><code>##

my ($this, $that, $other) = ("") x 3;
($this, $that, $other) = split (/\s+/, $line); 
# Now the worst case is you'll have a null string, not undef