(defun xah-regex (Xstring)
  "turn Xstring into a emacs lisp regex string.
Created: 2025-07-19
Version: 2025-07-19"
  (interactive)
  (let ()
3
 ))


;; HHHH------------------------------

;; xah regex special chars


;; HHHH------------------------------

;; c:/Users/xah/web/xahlee_info/comp/unicode_math_brackets.html

 ;; “ ” , ‘ ’ 
;; for literal, maybe

 ;; 「 」 , 『 』
 ;; for char class

 ;; 〔 〕 , 〘 〙 , ⦗ ⦘ 
;; for capture

;; White variants ⦅ ⦆ , 〚 〛 , ⦃ ⦄ 

;; 〈 〉 , 《 》

;; 【 】 , 〖 〗 

;; 2025-07-17
;; regex special characters 

;; .

;; *
;; +
;; ?

;; *?
;; +?
;; ??

;; []
;; [^]

;; ^
;; $
;; \

;; [:ascii:]
;; [:alnum:]
;; [:alpha:]
;; [:blank:]
;; [:cntrl:]
;; [:digit:]
;; [:graph:]
;; [:lower:]
;; [:multibyte:]
;; [:nonascii:]
;; [:print:]
;; [:punct:]
;; [:space:]
;; [:unibyte:]
;; [:upper:]
;; [:word:]
;; [:xdigit:]

;; ‘\|’
;; ‘\{M\}’
;; ‘\{M,N\}’

;; ‘\( ... \)’
;; ‘\(?: ... \)’
;; ‘\(?NUM: ... \)’

;; ‘\DIGIT’
;; ‘\w’
;; ‘\W’
;; ‘\sCODE’
;; ‘\SCODE’
;; ‘\cCODE’
;; ‘\CCODE’
;; ‘\`’
;; ‘\'’
;; ‘\=’
;; ‘\b’
;; ‘\B’
;; ‘\<’
;; ‘\>’
;; ‘\_<’
;; ‘\_>’