如何更改emacs软件包存储库？

Question

I use Emacs 24.3.1 on a Ubuntu 14.4. I'd like the list-packages command to list packages from the MELPA depository. I have followed the instructions here and here , to no avail. Specifically, following the advice given in the first link I added the following lines to my ~./emacs file:

(when (>= emacs-major-version 24)
  (require 'package)
  (package-initialize)
  (add-to-list 'package-archives '("melpa" . "http://melpa.milkbox.net/packages/") t)
  )

and restarted my emacs. This didn't have any effect, so I deleted the lines above and, following the advice given in the second link, added the following lines to my ~/.emacs file:

(setq package-archives '(("gnu" . "http://elpa.gnu.org/packages/")
                         ("marmalade" . "https://marmalade-repo.org/packages/")
                         ("melpa" . "http://melpa.milkbox.net/packages/")))

I restarted my emacs, but this had no effect either.

The reason I think that these attempts had no effect is that after each attempt I listed the available packages using the list-package command and did not find the package highlight-chars.el which I am interested in and which appears on the list at the MELPA website .

How can I instruct the list-packages command to search the MELPA depository?

Answer 1

The first thing you should check after restarting is the value of the variable in question.

Ch v package-archives RET

Whether or not it has the value you've tried to set is what's of primary interest.

If it doesn't, then presumably something else in your config is setting a conflicting value.

I would hazard a guess that you have the package-archives variable customized , and that the stored custom value is clobbering the value you're setting with setq .

For instance, the following init file would have the effect described:

(setq package-archives '(("gnu" . "http://elpa.gnu.org/packages/")
                         ("marmalade" . "https://marmalade-repo.org/packages/")
                         ("melpa" . "http://melpa.milkbox.net/packages/")))

(custom-set-variables
 ;; custom-set-variables was added by Custom.
 ;; If you edit it by hand, you could mess it up, so be careful.
 ;; Your init file should contain only one such instance.
 ;; If there is more than one, they won't work right.
 '(package-archives (quote (("gnu" . "http://elpa.gnu.org/packages/")))))
(custom-set-faces
 ;; custom-set-faces was added by Custom.
 ;; If you edit it by hand, you could mess it up, so be careful.
 ;; Your init file should contain only one such instance.
 ;; If there is more than one, they won't work right.
 )

Those custom-set-* forms could also be in a separate file, and therefore less obvious.

Try Mx customize-option RET package-archives RET

Select "Revert" and "Erase Customizations" to remove any value saved via this interface.

I'll speculate that the fact that Emacs' default initialisation of the package system happens after evaluating your init file may also be a factor here. People often recommend calling (package-initialize) in your init file but leave out the information that you want to have (setq package-enable-at-startup nil) in tandem with that, to prevent the initialisation happening twice. If that second initialisation occurs after the package-archives variable has changed again via customization, it might cause additional impediments to the system working the way you had wanted it to.