XXX.pm exports a function called XXX that you can put just about
anywhere in your Perl code to make it die with a YAML dump of the
arguments to its right.
The charm of XXX-debugging is that it is easy to type and rarely
requires parens and stands out visually so that you remember to remove
it.
XXX.pm also exports WWW, YYY and ZZZ which do similar debugging things.
To use Data::Dumper instead of YAML:
use XXX -dumper;
