Show HN: An XML-like document with spreadsheet formulas for values and undo-redo

I'm using it in guitktk [1]

> Also, you say you have "spreadsheet formulas", but is it possible to apply a formula to a range of nodes, like you can in an actual spreadsheet?

You can apply to all children of a node like len(`foo). In a different version, if you wanted to do that for an entire subtree, you could have something like len(list((`foo).dfs()))

[1] https://blog.asrpo.com/gui_toolkit