To be fair, my first thought was that generators solve this roughly with the same (JS-equivalent) semantics. But my second thought was that bidirectional JS gen

To be fair, my first thought was that generators solve this roughly with the same (JS-equivalent) semantics. But my second thought was that bidirectional JS generators are painful to write and use. They’re objectively better (particularly because they’re not inherently infectious when they yield), but they’re also unergonomic as heck.