toy html generation

htmltoy.el

(defun transform-args (args)
  (if (null args)
      ""
      (destructuring-bind (name value . rest) args
        (when (not (keywordp name))
          (signal 'wrong-type-argument (list name)))
        (concat " " (substring (symbol-name name) 1)
                "=\"" (format "%s" value) "\""
                (transform-args rest)))))

(defmacro deftag (tag)
  `(lexical-let ((tagname (symbol-name ',tag)))
     (defun ,tag (&rest rest)
       (let* ((length (length rest))
              (n (position t rest :key 'keywordp :from-end t))
              (args (if n (butlast rest (- length n 2)) '()))
              (content (if n (nthcdr (+ n 2) rest) rest)))
         (concat "<" tagname (transform-args args) ">"
                 (mapconcat 'identity
                            (mapcar (apply-partially 'format "%s") content)
                            " ")
                 "</" tagname ">")))))