Take a look at the source code and the number of files of phpdug.
click choose download at
http://www.kubelabs.com/phpdug/
and select 1.4.2
How much time and money would you need to create a phpdug?
Take a look at the demonstration of phpdug.
http://demos.kubelabs.com/PHPDug/
Did you imagine that the full phpdug script would need so many lines
of code?