my $file;
my $module;
my @installed;
my %installed;
my @standard;
my %standard;
my @non_standard;
my @INC_html = @INC;

map {s/perl/perl\/html/i;} @INC_html;

# Find all '.html' suffixed files in paths contained in the array @INC_html
find( sub { push @standard, $File::Find::name if -f _ && /\.html$/ },@INC_html);
 
foreach $file (@standard)
{
$file =~ /(.*lib\/)(.*)(\.html)/;
$file = $2;
$file =~ s/\//::/g;
}

# Find all '.pm' suffixed files in paths contained in the array @INC
find( sub { push @installed, $File::Find::name if -f _ && /\.pm$/ },@INC);
 
foreach $file (@installed)
{
$file =~ /(.*lib\/)(.*)(\.pm)/;
$file = $2;
$file =~ s/\//::/g;
}

# Build a look-up table (Hash) for the standard modules

@standard{@standard} = (1) x @standard;

# Look-up standard and non-standard modules

foreach $module (@installed)  
{
	unless(exists $standard{$module})
	{
		push @non_standard,$module;
	}
}