coverting "." serparated string to an array ??

[PHPycho]

Hello forums!!
Suppose we had list of strings in an array in a hierarchical form(separated by ".") as follows:

FOLDER1
FOLDER1.subfolder1
FOLDER1.subfolder2
FOLDER1.subfolder2.sub_subfolder1
FOLDER1.subfolder2.sub_subfolder12
.. can go upto n levels
FOLDER2
FOLDER2.subfolder1

I want to convert such string in an array , For example

array("FOLDER1" => array("subfolder1", "subfolder2" => array("sub_subfolder1","sub_subfolder12"), ...), "FOLDER2" => array("subfolder1"), ...etc)

How to accomplish this as it seems to be recursive.
Thanks in advance for the valueable tips and suggestions.

[sneakyimp]

You might find the [man]explode[/man] function useful. What I'm wondering though is at what depth you stop just nesting more arrays and actually have a value.

[Weedpacket]

That's the same question I have: "subfolder1" is a value but "subfolder2" is a key. That's going to cause grief later.