#!/usr/bin/env perl
use Modern::Perl;
use XML::Simple;
use Data::Dumper;

my $xml = XML::Simple->new();
my $in = $xml->XMLin('wiki.xml');
my %dict;
walk($in);

for (sort {$a cmp $b} keys %dict){
    say "$dict{$_}    $_";
}

sub walk {
    my $h = shift;
    for my $k (keys %$h){
        if($k eq 'content'){
	    add_to_dict($h->{$k});
	} elsif( ref($h->{$k}) eq 'HASH' ){
	    walk($h->{$k});
        }
    }
}

sub add_to_dict {
    my $text = shift;
    for my $w (split /\s+/, $text){
	$dict{$w}++;
    }
}