[ACCEPTED]-What is "with-eval-after-load" in Emacs Lisp-elisp

Accepted answer
Score: 63

From etc/NEWS:

* Lisp Changes in Emacs 24.4
** New macro `with-eval-after-load'.
This is like the old `eval-after-load', but better behaved.

Emacs 24.4 was released on 20th October 12 2014.

eval-after-load is considered ill-behaved because 11 it is a function, not a macro, and thus 10 requires the code inside it to be quoted, which 9 means that it cannot be byte-compiled. It 8 also accepts only one form, so if you have 7 more than one, you need to use progn. For example:

(eval-after-load "foo"
     (setq foo 42)
     (setq bar 17)))

The 6 equivalent version with with-eval-after-load would be:

(with-eval-after-load "foo"
  (setq foo 42)
  (setq bar 17))

As noted 5 by Clément in a comment, one disadvantage of with-eval-after-load is 4 that you cannot rely on macros defined in 3 the module in question, while with eval-after-load you 2 can be sure that such macros are defined 1 and available to use. This was discussed on emacs-devel.

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