#!/usr/bin/perl -wCSD

use strict;
use warnings;

use YAML::XS;
use Scalar::Util qw(looks_like_number);

my ($file, $option) = @ARGV;

unless (defined($file)) {
    print {*STDERR} ("1st parameter 'file' is not defined\n");
    exit (1);
}
unless (defined($option)) {
    print {*STDERR} ("2nd parameter 'option' is not defined\n");
    exit (1);
}

my $yaml = YAML::XS::LoadFile($file);
my $valref = \$yaml;

my @path = split(/\./, $option);
my $delete_element = pop(@path);

for my $component (@path) {
    if (ref($valref) eq 'SCALAR' && defined(${$valref})) {
        print {*STDERR} ("Key resolved to a SCALAR at '$component'; cannot continue.\n");
        exit (1);
    }
    elsif (looks_like_number($component) && (! defined(${$valref}) || ref(${$valref}) eq 'ARRAY')) {
        $valref = \${$valref}->[$component];
    }
    elsif (! defined(${$valref}) || ref(${$valref}) eq 'HASH') {
        $valref = \${$valref}->{$component};
    }
    else {
        print {*STDERR} ("Key resolved to a " . ref(${$valref}) . " reference; refusing to overwrite.\n");
        exit (1);
    }
}

delete ${$valref}->{$delete_element};

YAML::XS::DumpFile($file, $yaml);