Function to select repls as the current active connection

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## master (unreleased)
 
+### New features
+
+* [#190](https://github.com/clojure-emacs/inf-clojure/pull/190): Helper function `inf-clojure-set-repl` to select inf-clojure process buffer.
+
 ### Bugs fixed
 
 * [#152](https://github.com/clojure-emacs/inf-clojure/issues/152): Sanitize should only remove whitespace at the end of a command.

README.md

@@ -316,6 +316,17 @@ one process, this does the right thing.  If you run multiple
 processes, you might need to change `inf-clojure-buffer` to
 whichever process buffer you want to use.
 
+You can use the helpful function `inf-clojure-set-repl`. If called in
+an inf-clojure repl buffer, it will assign that buffer as the current
+connection (`(setq inf-clojure-buffer (current-buffer)`). If you are
+not in an inf-clojure repl buffer, it will offer a choice of
+acceptable buffers to set as the repl buffer. If called with a prefix,
+it will always give the list even if you are currently in an
+acceptable repl buffer. Renaming buffers will greatly improve the
+functionality of this list; the list "project-1: clojure repl",
+"project-2: cljs repl" is far more understandable than "inf-clojure",
+"inf-clojure<2>".
+
 #### REPL Type
 
 An `inf-clojure` REPL has an associated type. The available types can be

inf-clojure.el

@@ -199,6 +199,38 @@ has been found.  See also variable `inf-clojure-buffer'."
       (unless no-error
         (error "No Clojure subprocess; see variable `inf-clojure-buffer'"))))
 
+(defun inf-clojure-repl-p ()
+  "Indicates if current buffer is an inf-clojure repl.
+Checks the mode and that there is a live process."
+  (and (derived-mode-p 'inf-clojure-mode)
+       (get-buffer-process (current-buffer))
+       (process-live-p (get-buffer-process (current-buffer)))))
+
+(defun inf-clojure-repls-list ()
+  "Return a list of all known inf-clojure repls."
+  (let (repl-buffers)
+    (dolist (b (buffer-list))
+      (with-current-buffer b
+        (when (inf-clojure-repl-p)
+          (push (buffer-name b) repl-buffers))))
+    repl-buffers))
+
+(defun inf-clojure-set-repl (always-ask)
+  "Set an inf clojure buffer as the active repl.
+If in a repl already, use that unless a prefix is used (or
+ALWAYS-ASK).  Otherwise get a list of all active inf-clojure
+repls and offer a choice.  Recommended to rename buffers as they
+are created with `rename-buffer`."
+  (interactive "P")
+  (if (and (not always-ask)
+           (inf-clojure-repl-p))
+      (setq inf-clojure-buffer (current-buffer))
+    (let ((repl-buffers (inf-clojure-repls-list)))
+     (if (> (length repl-buffers) 0)
+         (when-let ((repl-buffer (completing-read "Use for repl: " repl-buffers nil t)))
+           (setq inf-clojure-buffer (get-buffer repl-buffer)))
+       (user-error "No buffers have an inf-clojure process")))))
+
 (defvar-local inf-clojure-repl-type nil
   "Symbol to define your REPL type.
 Its root binding is nil and it can be further customized using
@@ -242,6 +274,15 @@ mode.  Default is whitespace followed by 0 or 1 single-letter colon-keyword
 \(as in :a, :c, etc.)"
   :type 'regexp)
 
+(defun inf-clojure--modeline-info ()
+  "Return modeline info.
+Either \"not connected\" or \"repl-type: buffer-name\""
+  (if (and (bufferp inf-clojure-buffer)
+           (buffer-live-p inf-clojure-buffer))
+      (with-current-buffer inf-clojure-buffer
+        (format "%s: %s" inf-clojure-repl-type (buffer-name (current-buffer))))
+    "not connected"))
+
 (defvar inf-clojure-mode-map
   (let ((map (copy-keymap comint-mode-map)))
     (define-key map (kbd "C-x C-e") #'inf-clojure-eval-last-sexp)
@@ -326,14 +367,31 @@ mode.  Default is whitespace followed by 0 or 1 single-letter colon-keyword
         ["Quit REPL" inf-clojure-quit]))
     map))
 
+;;;###autoload
+(defcustom inf-clojure-mode-line
+  '(:eval (format " inf-clojure[%s]" (inf-clojure--modeline-info)))
+  "Mode line lighter for cider mode.
+
+The value of this variable is a mode line template as in
+`mode-line-format'.  See Info Node `(elisp)Mode Line Format' for details
+about mode line templates.
+
+Customize this variable to change how inf-clojure-minor-mode
+displays its status in the mode line.  The default value displays
+the current connection.  Set this variable to nil to disable the
+mode line entirely."
+  :type 'sexp
+  :risky t)
+
 ;;;###autoload
 (define-minor-mode inf-clojure-minor-mode
   "Minor mode for interacting with the inferior Clojure process buffer.
 
 The following commands are available:
 
 \\{inf-clojure-minor-mode-map}"
-  :lighter "" :keymap inf-clojure-minor-mode-map
+  :lighter inf-clojure-mode-line
+  :keymap inf-clojure-minor-mode-map
   (setq-local comint-input-sender 'inf-clojure--send-string)
   (inf-clojure-eldoc-setup)
   (make-local-variable 'completion-at-point-functions)
@@ -671,7 +729,7 @@ process buffer for a list of commands.)"
           (inf-clojure-mode)
           (setq-local inf-clojure-repl-type repl-type)
           (hack-dir-local-variables-non-file-buffer))))
-  (setq inf-clojure-buffer "*inf-clojure*")
+  (setq inf-clojure-buffer (get-buffer "*inf-clojure*"))
   (if inf-clojure-repl-use-same-window
       (pop-to-buffer-same-window "*inf-clojure*")
     (pop-to-buffer "*inf-clojure*")))