#!/usr/bin/perl
use strict;
use warnings;

use Data::Dumper;

my %return;
my @value = qw( foo bar baz quux );

$_ = uc $_
    for @{ [ @return{ qw( a b c d ) } = @value ] };

print Dumper( \%return ), Dumper( \@value );

=begin output
$VAR1 = {
          'c' => 'baz',
          'a' => 'foo',
          'b' => 'bar',
          'd' => 'quux'
        };
$VAR1 = [
          'foo',
          'bar',
          'baz',
          'quux'
        ];