x=5; y=7;
PUT DATA (x,y);

##</code><code>##

x=5 y=7

##</code><code>##

use Data::Dumper;
sub show {
  local $Data::Dumper::Terse=1;
  local $SHOW::expr=shift;
  local $SHOW::val=eval { $expr };
  $SHOW::expr . ($@ ? " throws exception: $@" 
                    : ('='.Dumper($SHOW::expr)));
}