package MYPACKAGE;
[...]
my ($ab, $cd, $ef, ..., $yz) =
  map { ... some function of $_ ... } ('ab', 'cd', ..., 'yz');

##</code><code>##

my ($field1, ...) =
  map { __PACKAGE__ . '::' . $_ } ('field1', ...);
[...]
... $self->{$field1} ...

##</code><code>##

foreach (qw(ab cd ef ... yz)) { ??? };