@HeaderRecordNames   = qw/$RequestYear $RequestMonth $RequestDay $RequestSequence $RecordType $RecordSequence $Record/;
@HeaderRecordLengths = qw/A2           A2            A2          A4               A2          A2              A1486/;

...

my (@HeaderRecordNames) = unpack(@HeaderRecordLengths, $_);
my (@RecordNames[$Recordtype])=unpack(@RecordLengths[$RecordType]);

##</code><code>##

@HeaderRecordNames   = qw/RequestYear RequestMonth RequestDay RequestSequence RecordType RecordSequence Record/;
$HeaderRecordLengths = q/A2A2A2A4A2A2A1486/;

...

my @head = unpack($HeaderRecordLengths, $_);
my %Header = map {$HeaderRecordNames[$_] => $head[$_]} (0..$#head);
my @data = unpack($RecordLengths[$head{RecordType}], $Header{Record});
my %Record = map {$RecordNames[$_] => $data[$_]} (0..$#data);