define cider-eval-last-sexp-at-point

[zcaudate]

I'm hoping to have a functionality to be used for evaluating -> and ->> macros where:

---

given the form:

(-> (+ 1 1)
    (+ 1)
    (+ 1)
    (+ 1))

it is possible to have evalution at subsequent steps, ie:

(-> (+ 1 1)| ; => 2
    (+ 1)
    (+ 1)
    (+ 1))

(-> (+ 1 1)
    (+ 1)| ;=> 3
    (+ 1)
    (+ 1))

(-> (+ 1 1)
    (+ 1)
    (+ 1)| ;=> 4
    (+ 1))

(-> (+ 1 1)
    (+ 1)
    (+ 1)
    (+ 1)|) ;=> 5

---

The interaction would be to move the parenthesis forward to the point of the cursor, evaluate and then move the parenthesis back to the original position.

I tried but was a bit stuck. It'd be super useful for me if someone can implement it.

[bbatsov]

Funny enough something like this already exists. See 2db31b0

What I've implemented works only for top-level forms, but obviously we can use the same approach for inner forms as well.

[zcaudate]

Oh that's awesome. Let me have a play with it.

[zcaudate]

is this the function?

(defun cider-read-and-eval-defun-at-point ()
  "Insert the toplevel form at point in the minibuffer and output its result.
The point is placed next to the function name in the minibuffer to allow
passing arguments."
  (interactive)
  (let* ((fn-name (cadr (split-string (cider-defun-at-point))))
         (form (format "(%s)" fn-name)))
    (cider-read-and-eval (cons form (length form)))))

So is it possible to change the behaviour by replacing cider-defun-at-point with something like cider-current-form-at-point?

[bbatsov]

No, the function is cider-eval-defun-to-point. Seems you want to create a variant of it - cider-eval-sexp-to-point.

[zcaudate]

I have this function:

(defun cider-eval-sexp-to-point ()
  (interactive)
  (let* ((begin (save-excursion (up-list) (backward-list) (point)))
         (code  (buffer-substring-no-properties begin (point)))
         (code  (concat code '(41))))
    (cider-interactive-eval code)))

however, using cider-interactive-eval, it prints the code => res which causes an error.

Is there a way to add a ;; before the string to comment out the result before printing? i.e
;;=> res