#! perl

# same url as used in "selection"
my $url =
   qr{(
      (?:https?|ftp|news|mailto|file)://[ab-zA-Z0-9\-\@;\/?:&=%\$_.+!*\x27(),~]+
      [ab-zA-Z0-9\-\@;\/?:&=%\$_+!*\x27(),~]   # do not include a trailing dot, its wrong too often
   )}x;

sub on_line_update {
   my ($term, $row) = @_;

   # fetch the line that has changed
   my $line = $term->line ($row);
   my $text = $line->t;

   # find all urls (if any)
   while ($text =~ /$url/g) {
      my $rend = $line->r;

      # mark all characters as underlined. we _must_ not toggle underline,
      # as we might get called on an already-marked url.
      $_ |= urxvt::RS_Uline
         for @{$rend}[ $-[1] .. $+[1] - 1];

      $line->r ($rend);
   }

   ()
}