read_tables.lisp

(defvar *previous-readtables* nil)
(defmacro enable-toml-syntax ()
  '(eval-when (:compile-toplevel :load-toplevel :execute)
    
    (push *readtable* *previous-readtables*)
    (setq *readtable* (copy-readtable))
    
    (set-macro-character #\[ 'read-left-bracket)
    ; more calls to (set-macro-character)
    ...))
 
(defmacro disable-toml-syntax ()
  '(eval-when (:compile-toplevel :load-toplevel :execute)
    (setq *readtable* (pop *previous-readtables*))))
 
(defun parse (contents)
  (let ((result nil))
    (with-input-from-string (in contents)
      (enable-toml-syntax)
      (setq result (read in))
      (disable-toml-syntax))
    result))