You can actually do this with Cursive, although it’s hidden. Go to Help->Edit custom properties…, and add idea.is.internal=true in the editor that opens. Then restart your IDE and you’ll have a new item in your Tools menu, Start IDE REPL. That’s a REPL on your open IDE instance.

Just what I was after — thanks Colin! I’m curious, is this on track to be an official, documented Cursive feature? And, is the IDE REPL an nREPL/socket-exposed REPL which I could somehow configure as a standard deps-aware Cursive remote REPL?

I’m not sure about making this a documented feature or not. At the moment it’s hidden, but not very hidden. The IDE REPL isn’t a network REPL, no, it just evaluates its forms directly. However there under Help->Edit Custom VM Options you can add -Dide.repl.server.port=40000 and you’ll get a socket REPL listening on that port.

Neat, thanks! An enlightening encounter with the streaming-/RPC-REPL divide, for me. Might it be possible/desirable to implement the IDE REPL as an nREPL or pREPL, to enable easier programmatic interaction with IntelliJ via Clojure? If so, would a GitHub issue for the same be welcome?

No, thanks - it used to use nREPL, but then I switched it to a socket REPL. If you connect to it from the Cursive Remote REPL, that will construct a prepl-like protocol over that connection so it will work in an RPC fashion. If you’re connecting from something else you’ll have to do that bit yourself. It should be fairly easy to set up a prepl over that connection from the client, I think.

The justification for that is that it’s easier to start a socket REPL from a bare socket, so I can use IntelliJ’s machinery to listen for a socket connection without having to load Clojure itself. Otherwise loading nREPL will necessarily load Clojure at IDE startup (which currently happens anyway, but I’m working to fix that over time).

Gotcha, I see. Thanks for all the info, I really appreciate it.

Does the Cursive remote REPL use Unrepl to establish that pREPL protocol? Or a similar solution you’ve implemented?

It’s a home-grown thing based on prepl. It’s structured in both directions like nREPL, which allows a few things, principally executing a form in a namespace other than *ns*. This is used when you send a form from a file to the REPL.