;;; -*- lexical-binding: t -*-
;;
;; this file:
;;   https://dataswamp.org/~incal/emacs-init/ll/ll-abc.el
;;
;; --------------------------------------------------------------------------

(require 'cl-lib)
(cl-pushnew "." load-path :test #'string=)
(require 'luki-lisp)

;; --------------------------------------------------------------------------

(defun alphabet (&optional as-list)
  (let ((abc "a b c d e f g h i j k l m n o p q r s t u v w x y z"))
    (if as-list
        (cl-remove ?\s (string-to-list abc))
      abc)))

;; (alphabet)                ; a b c d e f g h i j k l m n o p q r s t u v w x y z
;; (alphabet 'as-list)       ; (97 98 99 100 101 102 103 104 105 106 107 108 ...)
;; (--- (alphabet 'as-list)) ; 26

;; --------------------------------------------------------------------------

(defun echo-alphabet (&optional num)
  (interactive "P")
  (let ((as-list (alphabet 'as-list)))
    (or num (setq num (--- as-list)))
    (let* ((part      (cl-subseq as-list 0 num))
           (str-list  (mapcar (L (c) (char-to-string c)) part))
           (str-almost (@f "%s" str-list))
           (str        (substring str-almost 1 (1- (--- str-almost)))))
      ($ str))))

(defalias 'abc #'echo-alphabet)

;; (echo-alphabet   2) ; a b
;; (echo-alphabet  -2) ; a b c d e f g h i j k l m n o p q r s t u v w x
;; (echo-alphabet  10) ; a b c d e f g h i j
;; (echo-alphabet -10) ; a b c d e f g h i j k l m n o p

;; --------------------------------------------------------------------------

(<- 'll-abc)