Autovivification trick

Minimal example exhibiting a double reference autovivification trick (learnt from Brian McCauley in a clpmisc thread) to convert a list of structured strings as that below the __END__ token to a complex data structure as that illustrated by the output of the program. More details follow.

#!/usr/bin/perl

use strict;
use warnings;
use Data::Dumper;

my %dirhash;
while (<DATA>) {
    chomp;
    my $last=\\%dirhash;
    $last=\$$last->{$_} for split qr|/|;
}

print Dumper \%dirhash;

__END__
/file.txt
/a/file.txt
/a/b/c
/a/b/c/file.txt
/z/m/w/file.txt
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