use constant { FOO => 1, BAR => 2 };

##</code><code>##

my @num_to_name = qw(FOO BAR);

##</code><code>##

my $thing = FOO;
print "Thing = ".$num_to_name[$thing]."\n";

##</code><code>##

my @num_to_name;
BEGIN {
    @num_to_name = qw(FOO BAR);
    for my $number ( 0 .. $#things) {
        *blah = eval "*My::Package::".$things[$number];
        *blah = sub { $number };
    }
}