#! perl

sub on_keyboard_command {
   my ($self, $cmd) = @_;

   $cmd eq "selection:rot13"
      and $self->selection (map { y/A-Za-z/N-ZA-Mn-za-m/; $_ } $self->selection);

   ()
}

my @patterns = (
   # urls
   qr{ ([a-z0-9.+\-]+://[ab-zA-Z0-9\-\@;\/?:&=%\$_.+!*\x27(),]+) }x,

   # shell-like argument quoting
   qr{\G\s*(
      (?:
         [^"'\\ \t]+
         | \\.
         | " ([^\\"]+ | \\. )* "
         | ' [^']* '
      )+
   )}xs,
);

sub on_sel_extend {
   my ($self) = @_;

   my ($row, $col) = $self->selection_mark;
   my $line = $self->line ($row);
   my $offset = $line->offset_of ($row, $col);
   my $text = $line->t;

   for my $regex (@patterns) {
      while ($text =~ /$regex/g) {
         if ($-[1] <= $offset and $offset <= $+[1]) {
            $self->selection_beg ($line->coord_of ($-[1]));
            $self->selection_end ($line->coord_of ($+[1]));
            return 1;
         }
      }
   }

   ()
}