el.el

;; https://twitter.com/supermomonga/status/889235209782046720
;;
;; https://twitter.com/hchbaw/status/895745817897689088
;; https://twitter.com/hchbaw/status/895984112988692481
(defmacro my-eflet (specs &rest body)
  (declare (indent 1))
  (let ((garg (cl-gensym "args--")))
    `(cl-flet (,@(loop for (n b) in specs
                       collect
                       `(,@(pcase b
                             (`(lambda ,arg . ,body) `(,n ,arg ,@body))
                             (_ `(,n (&rest ,garg) (apply ,b ,garg)))))))
       ,@body)))

(my-eflet ((my-1+ (apply-partially '+ 1))
           (my-snoc (lambda (a d) (cons d a))))
  (list
   (my-1+ 1)
   (mapcar #'my-1+ '(1 2 3))
   (not (boundp 'my-1+))

   (my-snoc 'a 'b)))
;=> (2 (2 3 4) t (b . a))

(disassemble
 #'(lambda (&rest args--8025)
     (apply
      (lambda (a d)
        (cons d a))
      args--8025)))

;; byte code:
;;   args: (&rest args--8025)
;; 0       constant  apply
;; 1       constant  <compiled-function>
;;       args: (a d)
;;     0       varref    d
;;     1       varref    a
;;     2       cons
;;     3       return
;;
;; 2       varref    args--8025
;; 3       call      2
;; 4       return

(disassemble
 #'(lambda (a d) (cons d a)))

;; byte code:
;;   args: (a d)
;; 0       varref    d
;; 1       varref    a
;; 2       cons
;; 3       return