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Enable multiple REPLs #186

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3d2d914
Add functions for multiple REPLs
zauster Sep 28, 2025
583aba2
Make sulia-snail--port-in-use-p OS independent
zauster Oct 19, 2025
3de465b
First take on REPL cleanup
zauster Oct 19, 2025
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214 changes: 175 additions & 39 deletions julia-snail.el
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Original file line number Diff line number Diff line change
Expand Up @@ -95,8 +95,15 @@
(repeat :tag "List of strings" string)))
(make-variable-buffer-local 'julia-snail-extra-args)

(defcustom julia-snail-port 10011
(defcustom julia-snail-default-port 10011
"Default Snail server port for Emacs to connect to."
:tag "Default snail server port (local)"
:group 'julia-snail
:safe 'integerp
:type 'integer)

(defcustom julia-snail-port nil
"Snail server port of the buffer to connect to the REPL."
:tag "Snail server port (local)"
:group 'julia-snail
:safe 'integerp
Expand All @@ -112,14 +119,37 @@
(integer)))
(make-variable-buffer-local 'julia-snail-remote-port)

(defcustom julia-snail-repl-buffer "*julia*"
(defcustom julia-snail-repl-counter 0
"Counter of how many Julia REPL exist"
:tag "Counter for Julia REPL buffer"
:group 'julia-snail
:safe 'integerp
:type 'integer)

(defcustom julia-snail-default-repl-name "julia"
"Default buffer name to use for a Julia REPL."
:tag "Julia REPL buffer name"
:group 'julia-snail
:safe 'stringp
:type 'string)

;; At the moment, this variable is just a placeholder for the REPL
;; buffer name that will later on be set here. Not sure how to better
;; init an empty string variable
(defcustom julia-snail-repl-buffer ""
"Default buffer to use for Julia REPL interaction."
:tag "Julia REPL buffer"
:group 'julia-snail
:safe 'stringp
:type 'string)
(make-variable-buffer-local 'julia-snail-repl-buffer)

(defcustom julia-snail-repl-list '()
"Association list to store the julia REPL names and ports."
:tag "Julia REPL list"
:safe 'listp
:type 'list)

(defcustom julia-snail-terminal-type
(if (locate-library "vterm") :vterm :eat) ; default to :vterm for historical compatibility
"Which Emacs terminal emulator to use for the Julia REPL."
Expand Down Expand Up @@ -349,6 +379,29 @@ Uses function `compilation-shell-minor-mode'.")

;;; --- supporting functions

(defun julia-snail--port-in-use-p (port)
"Check if PORT is in use on the local machine using built-in Emacs Lisp.
Attempt to create a network process listening on the given PORT.
If the port is already in use, an error is raised, and the function returns t.
Otherwise, the function deletes the network process and returns nil."
(let ((process-connection-type nil)
(proc (ignore-errors (make-network-process
:name "test"
:server t
:service port))))
(if proc
(progn
(delete-process proc)
nil)
t)))

(defun julia-snail--find-free-port (start-port)
"Find a free port starting from START-PORT."
(let ((port start-port))
(while (julia-snail--port-in-use-p port)
(setq port (1+ port)))
port))

(defun julia-snail--copy-buffer-local-vars (from-buf)
"Copy Snail-related buffer-local variables from FROM-BUF to the current buffer."
(dolist (blv (buffer-local-variables from-buf))
Expand All @@ -363,8 +416,8 @@ Uses function `compilation-shell-minor-mode'.")
"Return the process buffer name for REPL-BUF."
(let ((real-buf (get-buffer repl-buf)))
(unless real-buf
(error "No REPL buffer found"))
(format "%s process" (buffer-name (get-buffer real-buf)))))
(julia-snail-switch-or-create-repl))
(format "%s process" (buffer-name (get-buffer julia-snail-repl-buffer)))))

(cl-defun julia-snail--message-buffer (repl-buf name message &key (markdown nil))
"Return a buffer named NAME linked to REPL-BUF containing MESSAGE."
Expand Down Expand Up @@ -528,6 +581,9 @@ Returns nil if the poll timed out, t otherwise."
(filename (julia-snail--efn (buffer-file-name (buffer-base-buffer))))
(module (if current-prefix-arg :Main (julia-snail--module-at-point)))
(line-num (line-number-at-pos block-start)))
;; If the repl-buffer is not set yet, ask to create or switch to one
(if (not (get-buffer julia-snail-repl-buffer))
(julia-snail-switch-or-create-repl))
(julia-snail--flash-region block-start block-end)
(if (and allow-send-to-repl
(consp current-prefix-arg) (> (car current-prefix-arg) 4))
Expand Down Expand Up @@ -587,7 +643,7 @@ Returns nil if the poll timed out, t otherwise."
(copy-file (file-truename f) (concat snail-remote-dir (file-name-directory f)) t)))))
snail-remote-dir))

(defun julia-snail--launch-command ()
(defun julia-snail--launch-command (port)
(let* ((extra-args (if (listp julia-snail-extra-args)
(mapconcat 'identity julia-snail-extra-args " ")
julia-snail-extra-args))
Expand All @@ -607,8 +663,8 @@ Returns nil if the poll timed out, t otherwise."
(string-equal "scp" remote-method)
(string-equal "scpx" remote-method))
(format "ssh -t -L %1$s:localhost:%2$s %3$s %4$s %5$s -L %6$s"
julia-snail-port
(or julia-snail-remote-port julia-snail-port)
port
(or julia-snail-remote-port port)
(concat
(if remote-user (concat remote-user "@") "")
remote-host)
Expand All @@ -629,7 +685,8 @@ Returns nil if the poll timed out, t otherwise."
(defun julia-snail--start (source-buf)
"Underlying command for julia-snail invocation.
Supports multiple terminal implementations."
(let* ((launch-command (julia-snail--launch-command))
(let* ((port (julia-snail--find-free-port julia-snail-default-port)) ;; find a new port
(launch-command (julia-snail--launch-command port))
;; XXX: Set the error color to red to work around breakage relating to
;; some color themes and terminal combinations, see
;; https://github.com/gcv/julia-snail/issues/11
Expand All @@ -641,27 +698,43 @@ Supports multiple terminal implementations."
(default-directory (if (file-remote-p default-directory)
(expand-file-name "~")
default-directory)))
(let ((terml-buf
;; first, start a REPL process in a new buffer
(cond
;; vterm
((eq :vterm julia-snail-terminal-type)
(let ((vterm-shell launch-command)
(terml-buf (generate-new-buffer julia-snail-repl-buffer)))
(pop-to-buffer terml-buf)
(with-current-buffer terml-buf
(vterm-mode))
terml-buf))
;; eat
((eq :eat julia-snail-terminal-type)
(let ((terml-buf (eat launch-command t))
(repl-buffer-name julia-snail-repl-buffer))
(with-current-buffer terml-buf
(rename-buffer repl-buffer-name))
terml-buf))
;; unsupported value
(t
(user-error "unsupported value for julia-snail-terminal-type: %s" julia-snail-terminal-type)))))
(setq julia-snail-repl-counter (1+ julia-snail-repl-counter)) ;; increment the REPL counter
(let* (
;; set a buffer name including a counter
(new-repl-buffer-name (format "*%s:%s*" julia-snail-default-repl-name julia-snail-repl-counter))
(terml-buf
;; first, start a REPL process in a new buffer
(cond
;; vterm
((eq :vterm julia-snail-terminal-type)
(let ((vterm-shell launch-command)
(terml-buf (generate-new-buffer new-repl-buffer-name)))
;; Set buffer-local values to associate the buffer with a REPL
(setq julia-snail-port port)
(setq julia-snail-repl-buffer new-repl-buffer-name)
;; Keep count of the REPL buffer name and port
(setq julia-snail-repl-list
(append julia-snail-repl-list `((,new-repl-buffer-name . ,port))))
(pop-to-buffer terml-buf)
(with-current-buffer terml-buf
(vterm-mode))
terml-buf))
;; eat
((eq :eat julia-snail-terminal-type)
(let ((terml-buf (eat launch-command t))
(repl-buffer-name new-repl-buffer-name))
;; Set buffer-local values to associate the buffer with a REPL
(setq julia-snail-port port)
(setq julia-snail-repl-buffer new-repl-buffer-name)
;; Keep count of the REPL buffer name and port
(setq julia-snail-repl-list
(append julia-snail-repl-list `((,new-repl-buffer-name . ,port))))
(with-current-buffer terml-buf
(rename-buffer repl-buffer-name))
terml-buf))
;; unsupported value
(t
(user-error "unsupported value for julia-snail-terminal-type: %s" julia-snail-terminal-type)))))
;; then deal with some setup on that buffer
(with-current-buffer terml-buf
(when source-buf
Expand Down Expand Up @@ -743,7 +816,25 @@ returns \"/home/username/file.jl\"."
(julia-snail--clear-proc-caches process-buf)
(when process-buf
(kill-buffer process-buf)))
(setq julia-snail--process nil))
(setq julia-snail--process nil)
;; Clean up REPL list and counter
(let ((repl-buffer-name (buffer-name)))
;; Remove this REPL buffer from the REPL list
(setq julia-snail-repl-list
(delete (assoc repl-buffer-name julia-snail-repl-list) julia-snail-repl-list))
;; Decrement REPL counter if it's greater than 0
(when (> julia-snail-repl-counter 0)
(setq julia-snail-repl-counter (1- julia-snail-repl-counter)))
;; Reset julia-snail-repl-buffer in all source buffers that reference this REPL
(dolist (buf (buffer-list))
(with-current-buffer buf
(when (and (boundp 'julia-snail-repl-buffer)
(string= julia-snail-repl-buffer repl-buffer-name))
(setq julia-snail-repl-buffer ""))))
;; Port is automatically released when the Julia process dies,
;; but this ensures our tracking is clean
(setq julia-snail-port nil
julia-snail-repl-buffer "")))

(defun julia-snail--repl-enable ()
"REPL buffer minor mode initializer."
Expand Down Expand Up @@ -953,7 +1044,7 @@ When :async is t (default), return the request id. When :async is
nil, wait for the result and return it."
(declare (indent defun))
(unless repl-buf
(user-error "No Julia REPL buffer %s found; run julia-snail" julia-snail-repl-buffer))
(julia-snail-switch-or-create-repl))
(let* ((process-buf (get-buffer (julia-snail--process-buffer-name repl-buf)))
(originating-buf (current-buffer))
(module-ns (julia-snail--construct-module-path module))
Expand Down Expand Up @@ -1672,14 +1763,33 @@ evaluated in the context of MODULE."

;;; --- commands

;; ;;;###autoload
;; (defun julia-snail ()
;; "Start a Julia REPL and connect to it, or switch if one already exists.
;; The following buffer-local variables control it:
;; - `julia-snail-repl-buffer' (default: *julia*)
;; - `julia-snail-port' (default: 10011)
;; To create multiple REPLs, give these variables distinct values (e.g.:
;; *julia my-project-1* and 10012)."
;; (interactive)
;; (let ((source-buf (current-buffer))
;; (repl-buf (get-buffer julia-snail-repl-buffer)))
;; (if repl-buf
;; ;; Julia session exists
;; (progn
;; (with-current-buffer repl-buf
;; (setq julia-snail--repl-go-back-target source-buf))
;; (pop-to-buffer repl-buf))
;; ;; run a new Julia REPL in a terminal and load the Snail server file
;; (julia-snail--start source-buf))))


;;;###autoload
;; (defun julia-snail-multiple-repls ()
(defun julia-snail ()
"Start a Julia REPL and connect to it, or switch if one already exists.
The following buffer-local variables control it:
- `julia-snail-repl-buffer' (default: *julia*)
- `julia-snail-port' (default: 10011)
To create multiple REPLs, give these variables distinct values (e.g.:
*julia my-project-1* and 10012)."
"Start a new Julia REPLs if there is not yet one. If there is one, ask
the user if we should connect to it or create a new REPL. If the buffer
is already associated with a REPL, pop to it."
(interactive)
(let ((source-buf (current-buffer))
(repl-buf (get-buffer julia-snail-repl-buffer)))
Expand All @@ -1689,8 +1799,31 @@ To create multiple REPLs, give these variables distinct values (e.g.:
(with-current-buffer repl-buf
(setq julia-snail--repl-go-back-target source-buf))
(pop-to-buffer repl-buf))
;; run a new Julia REPL in a terminal and load the Snail server file
(julia-snail--start source-buf))))
(if (not julia-snail-repl-list)
;; No REPL buffers in list, run a new Julia REPL in a
;; terminal and load the Snail server file
(julia-snail--start source-buf)
;; else: There are REPLs, let the user choose one (or create a new one)
(julia-snail-switch-or-create-repl)))))

(defun julia-snail-switch-or-create-repl ()
"Ask the user if the current buffer should be associated with a new or
already present REPL buffer."
(interactive)
(let ((chosen-repl-name
(completing-read
"Create new or switch to REPL: "
(cons '("new") julia-snail-repl-list))))
(if (string= chosen-repl-name "new")
;; User wants a new REPL buffer
(julia-snail--start (current-buffer))
;; else: User has chosen some REPL, associate the current
;; buffer with it and pop to it
(save-excursion
(progn
(setq julia-snail-repl-buffer chosen-repl-name)
(setq julia-snail-port (cdr (assoc chosen-repl-name julia-snail-repl-list)))
(pop-to-buffer chosen-repl-name))))))

(defun julia-snail-send-line ()
"Send the line at point to the Julia REPL and evaluate it.
Expand Down Expand Up @@ -1778,6 +1911,9 @@ Currently only works on blocks terminated with `end'."
"Send the current buffer's file into the Julia REPL, and include() it.
This will occur in the context of the Main module, just as it would at the REPL."
(interactive)
;; If the repl-buffer is not set yet, ask to create or switch to one
(if (not (get-buffer julia-snail-repl-buffer))
(julia-snail-switch-or-create-repl))
(let* ((jsrb-save julia-snail-repl-buffer) ; save for callback context
(filename (julia-snail--efn (buffer-file-name (buffer-base-buffer))))
(module (or (julia-snail--module-for-file filename) '("Main")))
Expand Down