region-to-marusuji.el

(defvar marusuji-ary ["⓪" "①" "②" "③" "④" "⑤" "⑥" "⑦" "⑧" "⑨"
		      "⑩" "⑪" "⑫" "⑬" "⑭" "⑮" "⑯" "⑰" "⑱" "⑲"
		      "⑳" "㉑" "㉒" "㉓" "㉔" "㉕" "㉖" "㉗" "㉘" "㉙"
		      "㉚" "㉛" "㉜" "㉝" "㉞" "㉟" "㊱" "㊲" "㊳" "㊴"
		      "㊵" "㊶" "㊷" "㊸" "㊹" "㊺" "㊻" "㊼" "㊽" "㊾" "㊿" ])

(defun region-to-marusuji (beg end)
  (interactive "r")
  (let ((n (string-to-int (buffer-substring beg end))))
    (when (and (<= 0 n) (<= n 50))
      (delete-region beg end)
      (insert (aref marusuji-ary n)) )))