Use the alternate usage of sort:

foreach ( sort gs::long_strings_first @$raw_hash_keys_ar ) {
    #do_stuff;
}

package gs;
sub long_strings_first($$) {
    return 0 unless defined $_[0];
    return 0 unless defined $_[1];

    length $_[1] <=> length $_[0]
                 ||
        lc $_[1] cmp lc $_[0]
}

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Why did you check if $b is undefined and not $a? If there can be undefined values in the list to be sorted, both $a and $b could be undefined. I added the extra check.

In reply to Re: Accessing $a and $b of 'sort' across package boundaries by ikegami
in thread Accessing $a and $b of 'sort' across package boundaries by ff

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