I'm using a regex to check for illegal input in a CGI script. since there are rather a lot of variables I thought I'd write a subroutine to help me out. This is what I have written: 
#!/usr/bin/perl -w
#use strict;
use CGI::Carp qw(fatalsToBrowser warningsToBrowser);
use CGI ':standard';

my $one = "apple";
my $two =  "pear";
my $three = "ba\$\£na\¨na";

my @vars;
my $ILLEGAL_CHARS = qr/[^\w\.-\s\@\(\)\Ó,]/;


@vars = ($one,$two,$three);

($one,$two,$three) = legal(@vars);

print header(), start_html(-title => "fruits");

print "$one,$two,$three";

print end_html();


sub legal {

foreach $item (@vars) {
$item =~ s/$ILLEGAL_CHARS/_/g;
}

return @vars;

}

[download]
My questions are:

When I use strict I get syntax errors for every single part of the regex - how can I use strict?
I have included as allowed things like ',' and '( )' to make life more agreeable for the user. Is there still enough there to prevent tampering? Can I improve the regex?
Is the subroutine set okay or can I improve on that. General comments welcome.

With thanks.

In reply to cgi security regex in subroutine by jonnyfolk

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