@cgrand I'm don't understand, yet, how that helps when code has to run in the target. Just two streams I got already. But my code in the client doesn't help, when it has to run in the server.

2 streams are too restrictive. Some communication with the host closure is required. The fuzzy idea is upgrade repl to quarantined repl where you can put all the code you want and connect it to a host repl.

Then your quarantined code sees the host namespaces?

Only through a veil of reflection or serialization.

working on the cljs.analyzer ast at the moment

the expandable print of unrepl.print would be sooooo super valueable right now

print the wrong ast node and it just dumps thousands of line on you .. not nice

The elision system is the thing I got right so far.

Maybe I should stop there.

Clojure could definitely use a better printer that doesn't just use a global defmulti

I partially agree. More than print itself it's the tree walking.