Re: Suggestions for improvements to the *Completions* buffer

[Philip Kaludercic]

Juri Linkov <juri@linkov.net> writes:

>>> -    (define-key map "z" 'kill-current-buffer)
>>>      (define-key map "\M-g\M-c" 'switch-to-minibuffer)
>>> +    (define-key map "z" #'completion-kill-buffer)
>>> +    (define-key map [remap keyboard-quit] #'completion-quit)
>>> +    (define-key map [remap quit-window] #'switch-to-minibuffer)
>>
>> It seems that remapping quit-window to switch-to-minibuffer creates
>> issues when the completion buffer is not invoked by the minibuffer, but
>> e.g. by complete-symbol.  Binding it to completion-quit (defined above)
>> instead, might actually be more natural, as "q"/quit-window is expected
>> to close a window.
>
> Good point, so `q' should not be rebound from its standard command
> `quit-window'.  Like you noticed, currently `quit-window' fails
> to select the minibuffer window, but this is a bug, so this regression
> was reported in bug#52491.

Ok, great!

> Then "z" could be bound to a variant of `quit-window'
> that calls it with the argument KILL non-nil.

So something like this?

diff --git a/lisp/mail/smtpmail.el b/lisp/mail/smtpmail.el
index bd8aa611e9..95e7abdeae 100644
--- a/lisp/mail/smtpmail.el
+++ b/lisp/mail/smtpmail.el
@@ -78,6 +78,19 @@ smtpmail-smtp-server
   "The name of the host running SMTP server."
   :type '(choice (const nil) string))
 
+(defcustom smtpmail-smtp-server-alist '()
+  "Alist of SMTP servers for different addresses."
+  :type '(alist :key-type
+                (string :tag "Sender")
+                :value-type
+                (list (string :tag "SMTP Server")
+                      (natnum :tag "Service")
+                      (choice :tag "Stream type"
+                              (const :tag "Possibly upgrade to STARTTLS" nil)
+                              (const :tag "Always use STARTTLS" starttls)
+                              (const :tag "Never use STARTTLS" plain)
+                              (const :tag "Use TLS/SSL" ssl)))))
+
 (defcustom smtpmail-smtp-service 25
   "SMTP service port number.
 The default value would be \"smtp\" or 25."
@@ -706,13 +719,9 @@ smtpmail-user-mail-address
 (defun smtpmail-via-smtp (recipient smtpmail-text-buffer
                                    &optional ask-for-password
                                     send-attempts)
-  (unless smtpmail-smtp-server
+  (unless (or smtpmail-smtp-server smtpmail-smtp-server-alist)
     (smtpmail-query-smtp-server))
-  (let ((process nil)
-        (send-attempts (or send-attempts 1))
-       (host (or smtpmail-smtp-server
-                 (error "`smtpmail-smtp-server' not defined")))
-       (port smtpmail-smtp-service)
+  (let* ((process nil)
         ;; `smtpmail-mail-address' should be set to the appropriate
         ;; buffer-local value by the caller, but in case not:
         (envelope-from
@@ -727,6 +736,14 @@ smtpmail-via-smtp
                 (and from
                      (cadr (mail-extract-address-components from))))
               (smtpmail-user-mail-address))))
+         (send-attempts (or send-attempts 1))
+         (server (alist-get envelope-from smtpmail-smtp-server-alist
+                            (list smtpmail-smtp-server)
+                            nil #'string=))
+         (host (or (car server)
+                   (error "No known SMTP Server for %S" envelope-from)))
+         (port (or (cadr server)
+                   smtpmail-smtp-service))
        process-buffer
        result
        auth-mechanisms
@@ -757,7 +774,7 @@ smtpmail-via-smtp
            (setq result
                  (open-network-stream
                   "smtpmail" process-buffer host port
-                  :type smtpmail-stream-type
+                  :type (or (caddr server) smtpmail-stream-type)
                   :return-list t
                   :warn-unless-encrypted ask-for-password
                   :capability-command (format "EHLO %s\r\n" (smtpmail-fqdn))

> Like currently `ESC ESC ESC' can close the completion window
> by the special command `delete-completion-window', then the same
> command could be bound to `[remap keyboard-quit]' as well.

Sure, but what noticeable difference does this make?  It seems to me
that quitting or killing the completion buffer doesn't amount to much of
a difference, as *Completion* is rarely selected manually.

The only case I can think of where the difference could matter, is when
*Completion* is so large that you need to kill it.  But considering that
even with "C-h o TAB" the difference appears to be indistinguishable.
Quitting a window and requesting the came completion doesn't even reuse
the existing buffer.

>> The question is whether or not there is a need for a separate
>> switch-to-minibuffer binding (besides M-g M-c)?  Is keeping the
>> completions buffer active while returning to the minibuffer a real need?
>
> Good question.  If four key bindings (q, z, C-g, ESC ESC ESC)
> all will close the completions (first two using quit-window,
> and last two using delete-completion-window), then maybe we should have
> an easy-to-type keybinding that will switch to the minibuffer without
> closing the completions window?
>
> There is an easy-to-type keys <PgUp> and M-v to switch to the
> completions window, but no an easy-to-type key to switch back.
>
> It seems wrong for `q' to switch to the minibuffer without closing
> the window because `quit-window' implies that window should quit.
> But what key to use instead, I have no idea.

Seeing as <left> and <right> are bound to previous-completion and
next-completion, maybe <up> and <down> could be used for
completion/minibuffer switching?

Or to take inspiration from Protesilaos's MCT package, that switches
back to the minibuffer once next-completion and previous-completion
reaches the end/beginning of the buffer, without quitting the window.
With next-completion bound to TAB while TAB also jumps back to the
completion buffer, it would behave to just by cycling.

-- 
        Philip Kaludercic