Thanks! You might also like the introduction I wrote to the Bluefin docs, which has some similar content: https://hackage-content.haskell.org/package/bluefin/docs/Blu...

Yes, Xavier's book was really interesting. It's here: https://xavierleroy.org/control-structures/

It's missing some subtleties of capability-based effect systems (which Bluefin is). Maybe I should write to him.