use Parse::RecDescent;

$RD_HINT++;
$RD_WARN++;
#$RD_TRACE++;

my $grammar = q{
  Start: Expression(s) /\Z/
  Expression: LineNum Print
      | LineNum Goto
      | <error>
  Print: /print/i /\"/ /[\s\w]+/ /\"/
  { 
      print "$item[3]\n";
  }
  Goto: /goto/i LineNum
  {
      print "Seen a goto line $item[2]\n";
      # How do I seek back to line $item[2] of
      # the input?
  }
  LineNum: /\d+/
  };

my $parser = new Parse::RecDescent($grammar);

undef $/;
my $text = <>;

$parser->Start($text);