Most of what I'd say has been commented on already. However
I just wanted to remind you of the
escapeHTML
function. It's quite good at what it does so you could replace
some of your code with:
foreach my $in ($message, $name, $mail)
{
$in = $q->escapeHTML($in);
# and of course you can do your subs here to:
$in =~ s/\(b\)/<b>/ig; # ...
}
The escapeHTML function is of course provided by CGI.pm.
It doesn't come with the :standard set
use CGI qw/:standard/; so if you want to use
it that way you have to include it
use CGI qw/:standard escapeHTML/;. This of course
is not an issue if you're using CGI.pm with its object
interface (as I have assumed above).
Remember that that $in in the foreach loop
is an alias to the elements in the list we've created. So for
the first iteration of the loop, $in is the same as
$message and everything you do to it is done to
$message.
You also might be interested in looking at Damian Conway's
Regexp::Common module as it has a very elaborate smut
filter that would save you having to write one of your own.