inspector.el

inspector.el

(require 'cl)

(defvar inspector-id 0)

(defvar inspector-keymap
  (let ((keymap (make-sparse-keymap)))
    (define-key keymap (kbd "<tab>")
      (lambda ()
	(interactive)
	(save-excursion
	  (let ((value (get-text-property (point) 'inspector-value)))
	    (goto-char (field-beginning))
	    (delete-field)
	    (insert (inspector value))))))
    keymap))

(defun subinspector (x)
  (cond
   ((or (numberp x) (symbolp x) (stringp x))
    (prin1-to-string x))
    ((consp x)
     (propertize "(...)"
		 'inspector-value x
		 'field (incf inspector-id)
		 'keymap inspector-keymap
		 'front-sticky t
		 'rear-nonsticky t))
    (t
     "<unknown>")))

(defun inspector (x)
  (if (consp x)
      (format "(%s . %s)" (subinspector (car x)) (subinspector (cdr x)))
    (subinspector x)))

(defun inspect (x)
  (interactive "XLisp expression: ")
  (insert (inspector x)))

(provide 'inspector)