#!/bin/perl
use strict;
use warnings;
use Data::Dumper;
use File::Slurper qw(read_text);

sub parse_nested_brackets {
    my ($string) = @_;
    my $index = 0;
    return parse_nested_brackets_recursive($string, \$index);
}

sub parse_nested_brackets_recursive {
    my ($string, $index_ref) = @_;
    my %hash;
    my ($key, $value);

    while ($$index_ref < length($string)) {
        my $char = substr($string, $$index_ref, 1);
        $$index_ref++;

        if ($char eq '(') {
            my $nested_hash = parse_nested_brackets_recursive($string,
+ $index_ref);
            if (defined $key) {
                $hash{$key} = $nested_hash;
                $key = undef;
            } else {
                %hash = (%hash, %$nested_hash);
            }
        } elsif ($char eq ')') {
            if (defined $key && defined $value) {
                $hash{$key} = $value;
                $key = undef;
                $value = undef;
            }
            return \%hash;
        } elsif ($char =~ /\s/) {
            next;
        } else {
            if (!defined $key) {
                $key = $char;
            } elsif (!defined $value) {
                $value = $char;
            } else {
                $value .= $char;
            }
        }
    }

    return \%hash;
}

my $string = read_text shift;

my $hash = parse_nested_brackets($string);

print Dumper($hash);
[download]

It's not able to parse string to array.