Detect content in minibuffer

Detect content in minibuffer

[Miguel Guedes]

I'm using the following to query the size of the buffer associated with 
the minibuffer but it always returns 0 even when there is a message 
currently being displayed in the echo area (say, documentation by eldoc 
or anything else).  The aim is to not echo anything when there's 
currently content in the echo area.

I've tried:

(with-current-buffer (window-buffer (minibuffer-window))
   (unless (> 0 (buffer-size))
     .
     :
     .

and [0],

(with-current-buffer (get-buffer " *Echo Area 0*")
   (unless (> 0 (buffer-size))
     .
     :
     .

What's wrong with my approach?

--
[0] Found excerpt referring to the echo area as "*Echo Area 0*" at 
http://www.emacswiki.org/emacs/EchoArea

Re: Detect content in minibuffer

[Nicolas Richard]

Miguel Guedes <miguel.a.guedes@gmail.com> writes:

> I'm using the following to query the size of the buffer associated
> with the minibuffer but it always returns 0 even when there is a
> message currently being displayed in the echo area (say, documentation
> by eldoc or anything else).  The aim is to not echo anything when
> there's currently content in the echo area.

I guess there are two problems :
1. minibuffer is not the same as echo area. Try
M-: M-: (with-current-buffer (window-buffer (minibuffer-window)) (buffer-string))
(i.e. enter a recursive minibuffer) and then you get something.

2. the command loop erases the echo area before running commands, so
whenever you try running your code interactively, it'll report an empty
echo area. Try this instead:

(progn
  (message "foo!")
  (with-current-buffer " *Echo Area 0*"
    (format "Found string: %s" (buffer-string))))

Also, the functions current-message and with-temp-message might be of
interest to you. (But note that current-message also suffers the
problems of being cleared if you call it interactively !)

HTH,

-- 
Nico.

Re: Detect content in minibuffer

[Stefan Monnier]

> I'm using the following to query the size of the buffer associated with the
> minibuffer but it always returns 0 even when there is a message currently
> being displayed in the echo area (say, documentation by eldoc or anything
> else).  The aim is to not echo anything when there's currently content in
> the echo area.

You might like to try (current-message).

> (with-current-buffer (window-buffer (minibuffer-window))
>   (unless (> 0 (buffer-size))

For some reason, (window-buffer (minibuffer-window)) returns the " *Minibuf-0*"
buffer rather than the " *Echo Area 0*" buffer.

> (with-current-buffer (get-buffer " *Echo Area 0*")
>   (unless (> 0 (buffer-size))

This should work.  At least in my tests:

   M-: (progn (message "foob") (with-current-buffer " *Echo Area 0*"
   (message "%S" (buffer-size)))) RET

returns 4.


        Stefan