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

(require 'cl-lib)

(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 t) ; (97 98 99 100 101 102 103 104 105 106 107 108 ...)
;; (length (alphabet t))

(defun echo-alphabet (&optional num)
  (interactive "P")
  (or num (setq num (length (alphabet t))))
  (let*((part       (cl-subseq (alphabet t) 0 num))
        (str-list   (mapcar (lambda (c) (char-to-string c)) part))
        (str-almost (format "%s" str-list))
        (str        (substring str-almost 1 (1- (length str-almost)))) )
    (message str) ))

(defalias 'abc #'echo-alphabet)

;; (/ (expt (+ 2 (* 2 26)) 11) 8019876189)
;; (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

(provide 'abc)