Xah Talk Show 2022-12-08 杀杀演绎 Emacs Lisp 简介

• Emacs Lisp 介绍。十年前很多大陆 台湾 香港 朋友帮忙，也有很多海外朋友看我的　Emacs　教材。谢谢。

• elisp basics
• do a example to delete text between brackets.
• ELisp: Simple Emacs Lisp Examples

• intro to lisp basics. (Emacs) Lisp Basics
• cover eval-last-sexp, eval-region, eval-buffer

(defun xah-delete-text-in-bracket ()
  "吧跨号中的字母删掉.
version 2022-12-08"
  (interactive)
  (let (p1 p2)
    (search-backward "(" nil t)
    (forward-char 1)
    (setq p1 (point))
    (search-forward ")" nil t)
    (backward-char 1)
    (setq p2 (point))
    (delete-region p1 p2)
    (message "好了")
    ;;
    ))

(+ 3 4)

(+ 3 4.1)

(integerp 3)
;; t
;; nil

;; integer part of quotient
(/ 7 2) ; 3

(/ 7 2.0) ; 3.5

(/ 7 2.0)

(equal (string-to-number "3") 3)
(equal "3" 3)
(equal "3" (number-to-string 3))

(progn
(goto-char 50)
(insert "杀杀演绎")
)