Show HN: Document parsing 5B tokens on a single CPU thread

mit license: https://github.com/john-friedman/doc2struct

doc2struct is an algorithm that can parse documents fast on one thread. For example it can parse every every 2025 annual report 19GB in 40s.

It preserves nesting, does mild table cleaning, among other things.

It succeeds my earlier document parser https://github.com/john-friedman/doc2dict