tree_build.pl

#!/usr/bin/env perl                                                                                                                                                                                            [0/3]
use strict;
use warnings;
use Smart::Comments;


my @array = qw{a b c};

my $result = {};

my $r = $result;

sub walk {
    my $v = shift;
    my $value = shift;

    if ($value) {
        $r->{$v} = $value;
    } else {
        $r->{$v} = {};
    }

    return $r->{$v};
}

for (0..$#array) {
    if ( $_ == $#array ) {
        $r = walk($array[$_], [1, 2, 3]);
    } else {
        $r = walk($array[$_]);
    }
}

### $result