open REs, "< re_file" or die "can't read re_file: $!";
while (<REs>) {
  chomp;
  my $mode = substr($_, 0, 1, '');  # reverse-chop
  push @re, [ $mode, match_maker($_) ];
}
close REs;


# make me a match... ;)
sub match_maker {
  my $pat = shift;
  return eval qq{ sub { \$_[0] =~ $pat } };
}

##</code><code>##

for (@re) {
  my ($mode, $func) = @$_;
  if ($func->($string)) {  # this is your pattern match!
    if ($mode eq '+') { print "this is ok\n"; }
    else { print "this matched an exception\n"; }
  }
}