>> But i don't know how i can use this.

> Yeah, I'd be careful about the license.  I don't see one.
> You might contact one of these folks:
> https://svn.greenpeace.org/projects/custard/browser/doc/copyright.html

> x = { 'value':1, 'children': [
>   { 'value': 2, 'children': []},
>   {'value' : 3, 'children': [
>      { 'value':4, 'children':[] }
>      ]}
>   ]}
> ----
> {% recurse through children as node starting with x %}
> ...do something with node.
> {% endrecurse %}