* mu4e.el: be more helpful for the user when setting up mu4e

emacs/mu4e.el

@@ -34,8 +34,6 @@
 (require 'mu4e-send)
 (require 'mu4e-proc)
 
-(require 'mu4e-version) ;; auto-generated
-
 ;; mu4e-version.el is autogenerated, and defines mu4e-mu-version
 (require 'mu4e-version)
 
@@ -51,15 +49,15 @@
   :group 'mu4e
   :safe 'stringp)
 
-(defcustom mu4e-mu-binary "mu"
+(defcustom mu4e-mu-binary (executable-find "mu")
   "Name of the mu-binary to use; if it cannot be found in your
 PATH, you can specify the full path."
   :type 'file
   :group 'mu4e
   :safe 'stringp)
 
-(defcustom mu4e-maildir nil
-  "Your Maildir directory. When `nil', mu will try to find it."
+(defcustom mu4e-maildir (expand-file-name "~/Maildir")
+  "Your Maildir directory; by default, mu4e assumes ~/Maildir."
   :type 'directory
   :safe 'stringp
   :group 'mu4e)
@@ -114,27 +112,21 @@ show up in the UI), and KEY is a shortcut key for the query.")
   "Special folders for mm."
   :group 'mu4e)
 
-;; (defcustom mu4e-inbox-folder nil
-;;   "Your Inbox folder, relative to `mu4e-maildir', e.g. \"/Inbox\"."
-;;   :type 'string
-;;   :safe 'stringp
-;;   :group 'mu4e-folders)
-
-(defcustom mu4e-sent-folder nil
+(defcustom mu4e-sent-folder "/sent"
   "Your folder for sent messages, relative to `mu4e-maildir',
   e.g. \"/Sent Items\"."
   :type 'string
   :safe 'stringp
   :group 'mu4e-folders)
 
-(defcustom mu4e-draft-folder nil
+(defcustom mu4e-drafts-folder "/drafts"
   "Your folder for draft messages, relative to `mu4e-maildir',
   e.g. \"/drafts\""
   :type 'string
   :safe 'stringp
   :group 'mu4e-folders)
 
-(defcustom mu4e-trash-folder nil
+(defcustom mu4e-trash-folder "/trash"
   "Your folder for trashed messages, relative to `mu4e-maildir',
   e.g. \"/trash\"."
   :type 'string
@@ -340,6 +332,35 @@ in which case it will be equal to `:to'.)")
 
 
 ;; mm startup function ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(defun mu4e-create-maildir-maybe (dir)
+  "Offer to create DIR if it does not exist yet. Return t if the
+dir already existed, or has been created, nil otherwise."
+  (if (and (file-exists-p dir) (not (file-directory-p dir)))
+    (error "%s exists, but is not a directory." dir))
+  (cond
+    ((file-directory-p dir) t)
+    ((yes-or-no-p (format "%s does not exist yes. Create now?" dir))
+      (mu4e-proc-mkdir dir))
+    (otherwise nil)))
+
+(defun mu4e-check-requirements ()
+  "Check for the settings required for running mu4e."
+  (unless mu4e-maildir
+    (error "Please set `mu4e-maildir' to the full path to your
+    Maildir directory."))
+  (unless (mu4e-create-maildir-maybe mu4e-maildir)
+    (error "%s is not a valid maildir directory" mu4e-maildir))
+  (dolist (var '( mu4e-sent-folder
+		  mu4e-drafts-folder
+		  mu4e-trash-folder))
+    (unless (and (boundp var) (symbol-value var))
+      (error "Please set %S" var))
+    (let* ((dir (symbol-value var)) (path (concat mu4e-maildir dir)))
+      (unless (string= (substring dir 0 1) "/")
+	(error "%S must start with a '/'"))
+      (unless (mu4e-create-maildir-maybe path)
+	(error "%s (%S) does not exist" path var)))))
+
 (defun mu4e ()
   "Start mm. We do this by sending a 'ping' to the mu server
 process, and start the main view if the 'pong' we receive from the
@@ -347,11 +368,7 @@ server has the expected values."
   (interactive)
   (if (buffer-live-p (get-buffer mu4e-main-buffer-name))
     (switch-to-buffer mu4e-main-buffer-name)
-    (dolist (var '(mu4e-maildir mu4e-inbox-folder mu4e-outbox-folder
-		    mu4e-outbox-folder mu4e-sent-folder mu4e-drafts-folder
-		    mu4e-trash-folder))
-      (unless (and (boundp var) (symbol-value var))
-	(error "Please set %S" var)))
+    (mu4e-check-requirements)
     ;; explicit version checks are a bit questionable,
     ;; better to check for specific features
     (if (< emacs-major-version 23)