s/\b($searchterm)\b/<span class="hilite">$1<\/span>/gi

##</code><code>##

#$text =~ s|(?<!["/>=])\b([A-Za-z]+(?:[A-Z]\w+)+)|
#  $tags->{link}->($1, $opts)|egx
#  if !defined $opts->{implicit_links} or $opts->{implicit_links};
$text =~ s|(?<!["/>=])\b([A-Z][a-z0-9]+([A-Z][a-z0-9]*)+)|
  $tags->{link}->($1, $opts)|egx
  if !defined $opts->{implicit_links} or $opts->{implicit_links};