#list of regex-strings
my @regex =
(
    's/(a+)/\U$1/g',
    's/([bz]+)/XX/g',
);

#is now a list of subroutines
@regex = map { eval "\$sub = sub { \$_=\$_[0]; $_; \$_ }" } @regex;

##</code><code>##

my @text = 
(
    "aaaabbzz",
    "bbbyyy",
);

for my $t ( @text )
{
    print "org $t\n";
    for my $re ( @regex )
    {
        $t = &$re($t);
    }
    print "new  $t\n";
}