Can anyone show me code on how to build a tree of nodes recursively?

I have something that looks like this:

[AND[OR
[IN,@GeoCounty,%GeoCounty]
[IN,@GeoRegion,%GeoReion]
]
[OR
[IN,@Date1,@Date2]
[IN,%TimeMonth]
]
]

The AND'S, OR'S ,IN'S are the node name. the info after each comma is the data in the node.

So AND is root
OR is 1st descendant
1st IN is descendant of OR with @GeoCounty as its data.
2nd IN is descendant of same OR with @GeoRegion as its data.
Next OR is 2nd descendant of AND. etc.

Thanks,