widget for directory view

[Gábor Szabó <szabgab gmail com>]

I'd like to create a directory browser for some virtual directory where 
I have my own function that works like this:

@entries = list_dir($parent_dir);

I would like to have that nice directory browser that has small
squares with + signs
when the item is expandable and - when it is expanded.

Which widget should I use ?

Gabor