Support specifying just one command in project-switch-commands

* lisp/progmodes/project.el (project-switch-commands):
Describe the new possible type of value.
(project--switch-project-command):
New function, extract from project-switch-project.
(project-switch-project): If project-switch-commands's value is a
symbol, invoke that command without showing a menu.

Co-authored-by: Jiacai Liu <hello@liujiacai.net>

diff --git a/lisp/progmodes/project.el b/lisp/progmodes/project.el
index b6eea7e27e475d73688e07f25bd26a962e1c38d4..ba95ed094edf207be08834a11a2a4b257a372a67 100644 (file)
--- a/lisp/progmodes/project.el
+++ b/lisp/progmodes/project.el
@@ -1344,17 +1344,22 @@ Each element is of the form (COMMAND LABEL &optional KEY) where
 COMMAND is the command to run when KEY is pressed.  LABEL is used
 to distinguish the menu entries in the dispatch menu.  If KEY is
 absent, COMMAND must be bound in `project-prefix-map', and the
-key is looked up in that map."
+key is looked up in that map.
+
+The value can also be a symbol, the name of the command to be
+invoked immediately without any dispatch menu."
   :version "28.1"
   :group 'project
   :package-version '(project . "0.6.0")
-  :type '(repeat
-          (list
-           (symbol :tag "Command")
-           (string :tag "Label")
-           (choice :tag "Key to press"
-            (const :tag "Infer from the keymap" nil)
-            (character :tag "Explicit key")))))
+  :type '(choice
+          (repeat :tag "Commands menu"
+           (list
+            (symbol :tag "Command")
+            (string :tag "Label")
+            (choice :tag "Key to press"
+                    (const :tag "Infer from the keymap" nil)
+                    (character :tag "Explicit key"))))
+          (symbol :tag "Single command")))
 
 (defcustom project-switch-use-entire-map nil
   "Make `project-switch-project' use entire `project-prefix-map'.
@@ -1384,15 +1389,7 @@ are legal even if they aren't listed in the dispatch menu."
    project-switch-commands
    "  "))
 
-;;;###autoload
-(defun project-switch-project (dir)
-  "\"Switch\" to another project by running an Emacs command.
-The available commands are presented as a dispatch menu
-made from `project-switch-commands'.
-
-When called in a program, it will use the project corresponding
-to directory DIR."
-  (interactive (list (project-prompt-project-dir)))
+(defun project--switch-project-command ()
   (let* ((commands-menu
           (mapcar
            (lambda (row)
@@ -1423,6 +1420,20 @@ to directory DIR."
           (when (memq global-command
                       '(keyboard-quit keyboard-escape-quit))
             (call-interactively global-command)))))
+    command))
+
+;;;###autoload
+(defun project-switch-project (dir)
+  "\"Switch\" to another project by running an Emacs command.
+The available commands are presented as a dispatch menu
+made from `project-switch-commands'.
+
+When called in a program, it will use the project corresponding
+to directory DIR."
+  (interactive (list (project-prompt-project-dir)))
+  (let ((command (if (symbolp project-switch-commands)
+                     project-switch-commands
+                   (project--switch-project-command))))
     (let ((default-directory dir)
           (project-current-inhibit-prompt t))
       (call-interactively command))))