(author of treesheets here) not sure who username strlen is, but it's not me :)

But yes, TreeSheets was initially designed just to be perfect for my needs. It has existed since 2008 though, so it has plenty of general usability tweaks for others since.

The computational sub-language is indeed very weak. It can at least do `sum` though, which is 99% of my uses of spreadsheets :)