c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my @tags = (
   'consisting of: cat1: id1: 7: 20',
   'discouraged: cat1: id2: 39: 50',
   'most cases: cat2: id3: 59: 69',
   );
 ;;
 my %targets;
 ;;
 for my $tag (@tags) {
   my ($string, $cat, $id) = split /:\s+/, $tag;
   $targets{$string} = [ $cat, $id ];
   }
 ;;
 my ($rx_target) =
   map  qr{ \b (?: $_) \b }xms,
   join ' | ',
   map  quotemeta,
   reverse sort
   keys %targets
   ;
 ;;
 my $string = 'Titles consisting of a single word are discouraged, '
            . 'and in most cases are disallowed outright.'
            ;
 print qq{'$string'};
 ;;
 $string =~
   s{ ($rx_target) }
    {($targets{$1}[0]: $targets{$1}[1])$1($targets{$1}[0])}xmsg;
 print qq{'$string'};
"
'Titles consisting of a single word are discouraged, and in most cases are disallowed outright.'
'Titles (cat1: id1)consisting of(cat1) a single word are (cat1: id2)discouraged(cat1), and in (cat2: id3)most cases(cat2) are disallowed outright.'