Re: How do I find out, in a Lisp program, what is the current buffer?

[Eshel Yaron <me@eshelyaron.com>]

Hi Alan,

Alan Mackenzie <acm@muc.de> writes:

> I want to find out what is the current buffer, and I mean the REAL
> current buffer.
>
> In particular, if that is the minibuffer, I want to be told it's the (or
> a) minibuffer, not the buffer it was invoked from.  The function
> current-buffer won't do this.

My two cents: AFAICT, `current-buffer` does do this, in some sense at
least.  To see that, type `M-x (current-buffer) C-x C-e`, here Emacs
says "#<buffer *Minibuf-1*>".

Note that when you say `M-: (current-buffer) RET` the form is read in
the minibuffer, but it's evaluated in the original buffer.  That's why you
get the original buffer as the return value.
`M-: (current-buffer) C-x C-e` points at the minibuffer as expected OTOH.

> I want to use this for writing the current buffer into the new position
> info in the doc string (bug #67455).  Evaluating a defun in the
> minibuffer is different from evaluating one in *scratch*.
>
> Is there some way I can get this information from Lisp, or do I have to
> write a new C primitive?

IIUC, you need the buffer from which the form was read, not the one in
which it was evaluated.  Perhaps `read_internal_start` could store its
`stream` argument in some variable so if you immediately evaluate a form
with that variable it would tell you where it was read from.  It's just
a rough idea, though.


Good luck,

Eshel