From what you've said, your function takes a callback and two list, modifies the elements of both lists and returns a third list. Your function is insane.

( No, I misunderstood. It only modifies the first array which makes the rest of this post moot. The function is still pretty crazy, though )

Anyway, you seem to be asking how to create an array of aliases. It's actually possible with little work!

sub foo(\@) {
    my ($array) = @_;
    $_ = uc($_) for @$array;
}

my @array = qw( foo bar Foo Bar );
foo @{ sub { \@_ }->( grep /^[A-Z]/, @array ) };
print "$_\n" for @array;
[download]

foo
bar
FOO
BAR
[download]

Of course, an array wouldn't normally be used at all.

sub foo {
    $_ = uc($_) for @_;
}

my @array = qw( foo bar Foo Bar );
foo grep /^[A-Z]/, @array;
print "$_\n" for @array;
[download]

foo
bar
FOO
BAR
[download]