pi-repl

Minimal pi extension for collaborative REPL sessions using tmux.

pi-repl starts a shared Python, IPython, Julia, R, Haskell (GHCi), or Clojure REPL in tmux that you can attach to from another terminal window. You can work in the REPL directly, or ask pi to send and execute code there.

Interacting with a shared Julia REPL.

Current scope

Currently, pi-repl supports Python/IPython, Julia, R, Haskell (GHCi), and Clojure.

With pi-repl you can:

• start a shared REPL from pi
• attach to that REPL from another terminal window
• work in the REPL yourself as normal
• ask pi, in natural language, to run code in the shared Python/IPython, Julia, R, Haskell (GHCi), or Clojure REPL
• start, attach to, inspect, and stop a shared R REPL
• start, attach to, inspect, and stop a shared Haskell (GHCi) REPL
• start, attach to, inspect, and stop a shared Clojure REPL
• let pi read the raw shared REPL transcript for extra context when needed
• check which shared REPL sessions are running
• inspect which Python interpreter and environment the shared Python/IPython REPL is using with /repl env
• stop the shared REPL when you are done

Use /lab as a short alias for /repl.

Install

From npm:

pi install npm:pi-repl

From GitHub:

pi install https://github.com/omaclaren/pi-repl

Restart pi after installing.

Commands

Command	Description
/repl	Show usage
/lab	Alias for /repl
/repl python	Start the shared Python/IPython session with python
/repl ipython	Start the shared Python/IPython session with ipython
/repl julia	Start the shared Julia session with julia
/repl r	Start the shared R session with R
/repl ghci	Start the shared Haskell (GHCi) session with ghci
/repl clojure	Start the shared Clojure session with clojure
/lab python	Same as /repl python
/lab ipython	Same as /repl ipython
/lab julia	Same as /repl julia
/lab r	Same as /repl r
/lab ghci	Same as /repl ghci
/lab clojure	Same as /repl clojure
/repl status	Show running shared REPL sessions
/repl status python	Show status for the shared Python/IPython session
/repl status julia	Show status for the shared Julia session
/repl status r	Show status for the shared R session
/repl status ghci	Show status for the shared Haskell (GHCi) session
/repl status clojure	Show status for the shared Clojure session
/repl env	Show which interpreter and environment the shared Python/IPython REPL is using
/repl attach	Show how to attach from a new terminal window
/repl attach julia	Show how to attach to the shared Julia session
/repl attach r	Show how to attach to the shared R session
/repl attach ghci	Show how to attach to the shared Haskell (GHCi) session
/repl attach clojure	Show how to attach to the shared Clojure session
/repl stop	Stop the shared session if only one is running
/repl stop python	Stop the shared Python/IPython session
/repl stop julia	Stop the shared Julia session
/repl stop r	Stop the shared R session
/repl stop ghci	Stop the shared Haskell (GHCi) session
/repl stop clojure	Stop the shared Clojure session

For R, both /repl R and /repl r work. The same applies to /lab, /repl status, /repl attach, and /repl stop.

For Clojure, /repl clojure is canonical and /repl clj also works. The same applies to /lab, /repl status, /repl attach, and /repl stop.

Tools used by pi

pi-repl also exposes tools that pi can use internally. In normal use, you can just ask pi to run code in the shared REPL or use the /repl commands directly.

Tool	Description
repl_status	Inspect shared Python/IPython, Julia, R, Haskell (GHCi), and Clojure REPL state
repl_send	Execute code in the running shared Python/IPython, Julia, R, Haskell (GHCi), or Clojure session

Notes:

• repl_status is what pi uses to check which shared REPL sessions are currently running
• while a shared REPL is running, repl_status also exposes the raw session history log path
• pi can read that history file for context about what has already happened in the shared REPL
• the relevant shared session must already be running before repl_send
• you can ask pi naturally to run code in Python, IPython, Julia, R, Haskell, or Clojure; pi chooses the tool parameters internally
• for plain Python, print(...) is the safest way to get values back reliably
• in Haskell (GHCi), use normal interactive syntax such as let bindings or :{ ... :} blocks for multiline declarations
• in Clojure, use normal interactive syntax such as let, def/defn, or do forms for multiline code
• tool output includes both the submitted code and the captured output

Shared sessions

The default shared tmux session names are:

• pi-repl-python for Python/IPython
• pi-repl-julia for Julia
• pi-repl-r for R
• pi-repl-ghci for Haskell (GHCi)
• pi-repl-clojure for Clojure

The Python/IPython session can currently be launched in either:

• python mode
• ipython mode

Attaching

After running /repl attach, open a new terminal window and run the tmux command shown by pi. For example:

tmux attach -t pi-repl-python

Example workflow

/repl ipython
/repl env
/repl status
/repl attach

/repl julia
/repl status julia
/repl attach julia

/repl R
/repl status r
/repl attach r

/repl ghci
/repl status ghci
/repl attach ghci

/repl clojure
/repl status clojure
/repl attach clojure

Example requests once the REPL is running:

• run print(sys.executable) in the shared Python REPL
• inspect the current globals in the shared Python REPL
• in the shared Julia REPL, load LinearAlgebra
• now find the eigenvalues of [2 1; 1 2] in the shared Julia REPL
• in the shared R REPL, run mean(c(1, 2, 3, 4))
• in the shared Haskell REPL, run map (+1) [1,2,3]
• in the shared Clojure REPL, run (map inc [1 2 3])

Notes

• tmux is required.
• While a shared REPL is running, pi-repl keeps a raw transcript log of the tmux pane output for that session.
• That transcript is plain text and may include prompts, echoed input, output, and errors.
• /repl env is currently implemented for Python/IPython only.

Related extensions

pi-interactive-shell offers related but distinct functionality for interactive CLI sessions in pi, including overlay-based interaction and user take-over. pi-repl is focused specifically on shared tmux-backed REPL sessions.

License

MIT