added standalone swank; use prefix arg for elein-swank

elein.el

@@ -38,6 +38,11 @@
   :type 'string
   :group 'elein)
 
+(defcustom elein-standalone-swank-command "~/.lein/bin/swank-clojure"
+  "Leiningen 'swank-clojure' command for standalone execution."
+  :type 'string
+  :group 'elein)
+
 (defcustom elein-swank-buffer-name "*elein-swank*"
   "Buffer name for swank process."
   :type 'string
@@ -107,24 +112,47 @@
           elein-swank-host
           elein-swank-options))
 
+(defun elein-standalone-swank-command ()
+  "Build projectless lein swank command."
+  (unless (file-exists-p (expand-file-name elein-standalone-swank-command))
+    (error "can not find %s; use 'lein install swank-clojure VERSION' to install it"
+           elein-standalone-swank-command))
+  (format "%s %d :host %s %s"
+          (expand-file-name elein-standalone-swank-command)
+          elein-swank-port
+          elein-swank-host
+          elein-swank-options))
+
+(defun elein-burried-shell-command (command buffer)
+  "Same as `shell-command' but run process asynchronously, do not
+show output and burry the given BUFFER."
+  (flet ((display-buffer (buffer-or-name &optional not-this-window frame) nil))
+    (bury-buffer buffer)
+    (shell-command (concat command "&") buffer)))
+
+(defun elein-swank-process-filter (process output)
+  "Swank process filter to launch `slime-connect' when process is ready."
+  (with-current-buffer elein-swank-buffer-name (insert output))
+
+  (when (string-match "Connection opened on local port +\\([0-9]+\\)" output)
+    (slime-set-inferior-process
+     (slime-connect "localhost" (match-string 1 output))
+     process)
+    (set-process-filter process nil)))
+
 ;;;###autoload
-(defun elein-swank ()
-  "Launch lein swank and connect slime to it."
-  (interactive)
+(defun elein-swank (&optional prefix)
+  "Launch lein swank and connect slime to it.  Interactively, a
+PREFIX means launch a standalone swank session without a
+project."
+  (interactive "P")
   (let ((buffer (get-buffer-create elein-swank-buffer-name)))
-    (flet ((display-buffer (buffer-or-name &optional not-this-window frame) nil))
-      (bury-buffer buffer)
-      (elein-in-project-root (shell-command (concat (elein-swank-command) "&") buffer)))
-
-    (set-process-filter (get-buffer-process buffer)
-                        (lambda (process output)
-                          (with-current-buffer elein-swank-buffer-name (insert output))
-
-                          (when (string-match "Connection opened on local port +\\([0-9]+\\)" output)
-                            (slime-set-inferior-process
-                             (slime-connect "localhost" (match-string 1 output))
-                             process)
-                            (set-process-filter process nil))))
+    (if prefix
+      (elein-burried-shell-command (elein-standalone-swank-command) buffer)
+      (elein-in-project-root
+       (elein-burried-shell-command (elein-swank-command) buffer)))
+
+    (set-process-filter (get-buffer-process buffer) #'elein-swank-process-filter)
 
     (message "Starting swank..")))