What is this error? "Symbol's value as variable is void: nxml-mode-map"

Question

I want to create a command and a keybind to scan with tidy a full buffer. The keybinding has to be active only when editing XML files.

In my ~/.emacs.d/init.el file I've added the following lines:

(defun tidy-xml ()
  "Tidies the XML content in the buffer using `tidy'"
  (interactive)
  (shell-command-on-region
    (point-min) (point-max)
    "tidy -i -w 72 -q -xml"
    (current-buffer)
    t
    "*Error*"
    t))

(define-key nxml-mode-map "\C-c t" 'tidy-xml)

But when I open Emacs it returns the following warning:

Warning (initialization): An error occurred while loading ‘/home/jim/.emacs.d/init.el’:

Symbol's value as variable is void: nxml-mode-map

I'm not able to see where the error is. Can you give me a hand?

The error has actually nothing to do with the shell command. — Tobias, Oct 28 '19 at 19:54
The question appears to be a duplicate. Search the site for "variable is void" to see similar questions. — Drew, Oct 28 '19 at 20:02

score 2 · Answer 1 · answered Oct 28 '19 at 19:51

2

The variable nxml-mode-map is defined in the library nxml-mode. This library is not yet loaded when you try to execute the form (define-key nxml-mode-map "\C-c t" 'tidy-xml).
Replace that line with:

(eval-after-load "nxml-mode"
  (lambda ()
    (define-key nxml-mode-map "\C-c t" 'tidy-xml)))

That will delay the execution of the form contained in the lambda until the library nxml-mode is loaded.

answered Oct 28 '19 at 19:51

Tobias

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Or, since 24.4, use with-eval-after-load and then you can drop the (lambda () ...) wrapper. – phils Oct 28 '19 at 23:31

What is this error? "Symbol's value as variable is void: nxml-mode-map"

1 Answers1