How do I move the cursor to be just after the `>` character on the beggining of REPL evaluation?

Question

I am using Emacs and Slime to work on Common Lisp code and I would like to know the most efficient way to move the cursor to the beginning of the REPL> assessment.

For instance, modelling the cursor as "I", which keys should I press to move the cursor from this position:

NIL
REPL> (defvar lista-history-entries (reverse (mapcar #'url (mapcar #'htree:data 
                                                                   (with-data-unsafe "I" (history (history-path (current-buffer)))
                                                                     (alex:hash-table-keys (htree:entries history)))))))

Into this position:

NIL
REPL> "I"(defvar lista-history-entries (reverse (mapcar #'url (mapcar #'htree:data
                                                                   (with-data-unsafe (history (history-path (current-buffer)))
                                                                     (alex:hash-table-keys (htree:entries history)))))))

If I press C-a it brings me to the beginning of the line, which is only useful for my goal if the starting position is on the first line. If I press M-a it brings me to the NIL expression, just above the REPL. It is close and helpful. But I bet there is a way to be exactly at the beginning of the evaluation.

Answer 1

The slime REPL buffer is is REPL mode. You can get information about the mode with C-h m. That is useful in that it shows you the keymap for the mode, and among other things, you will see that C-c C-p is bound to slime-repl-previous-prompt. Here is an excerpt from the description:

REPL mode defined in ‘slime-repl.el’:
Major mode for interacting with a superior Lisp.
key             binding
---             -------

C-c     Prefix Command
C-j     slime-repl-newline-and-indent
RET     slime-repl-return
C-x     Prefix Command
ESC     Prefix Command
SPC     slime-space
  (this binding is currently shadowed)
,       slime-handle-repl-shortcut
DEL     backward-delete-char-untabify
C-<down>    slime-repl-forward-input
C-<return>  slime-repl-closing-return
C-<up>      slime-repl-backward-input
<return>    slime-repl-return

C-x C-e     slime-eval-last-expression

C-c C-c     slime-interrupt
C-c C-n     slime-repl-next-prompt
C-c C-o     slime-repl-clear-output
C-c C-p     slime-repl-previous-prompt
C-c C-s     slime-complete-form
C-c C-u     slime-repl-kill-input
C-c C-z     slime-nop
C-c ESC     Prefix Command
C-c I       slime-repl-inspect

M-RET       slime-repl-closing-return
M-n     slime-repl-next-input
M-p     slime-repl-previous-input
M-r     slime-repl-previous-matching-input
M-s     slime-repl-next-matching-input

C-h m is one of the first things I do when exploring an unfamiliar mode.

Answer 2

backward-sexp, bound to C-M-b by default`, would do it. Of course, if you’re nested inside several s–expressions then you would need to press it multiple times.

So perhaps you want beginning-of-defun, bound to C-M-a, instead.