I'm struggling to find again a c++ implementation of this I saw on github a while back. Does HN the hive mind remember?
https://github.com/fogleman/primitive
Only the UI is closed source. It's written in Objective-C and basically shells out to the Go code.
Edit: Also, if you would like some help maintaining it, I imagine plenty of fellow HN-ers (including me) would love to help.
[1] https://github.com/fogleman/primitive/pulls?q=is%3Aopen+is%3...