Re: using use-package

[Phillip Lord]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> Putting in the core is rather some distance from promoting as the "one
>> true way"
>
> FWIW, lots of use-package is designed to work around flaws in packages.
>
> E.g. the :load-path thingy should never be necessary since the package's
> own autoloads should already take care of that.

You are correct about the :load-path thingy, although I use this for my
own packages which I run "straight from source" as it where, rather than
install as a ELPA package proper.


> Or to take another example from https://github.com/jwiegley/use-package:
>
>    (use-package foo
>      :init
>      (setq foo-variable t)
>      :config
>      (foo-mode 1))
>
> For any properly written foo-mode, the above can be replaced with
>
>      (setq foo-variable t)
>      (foo-mode 1)
>
> and it should work just as well.


No, you are missing (several) points of use-package. First (and
trivially) the use-package statement groups everything syntactically.
So, it's more like:

(progn
  (setq foo-variable t)
  (foo-mode 1))

This is nicer because it groups all the configuration together, so you
can move, comment, delete or eval it all together. Of course, `progn'
achieves the same thing.

However, `use-package' also gives you configurable feedback on load
times. So if (require 'foo) takes a long time, use-package tells you,
and tells you how long it takes.

In your example,

(foo-mode 1)

will force an autoload. With use-package, also I can do

(use-package foo
  :defer t
  ;;;etc
  )

which will achieve the same. Or

(use-package foo
  :defer 10)

will load foo in the idle cycle.

Or

(use-package foo
  :ensure t)

will install from ELPA if `foo' is not present.

Or

(use-package foo
  :if window-system)

will only load foo (and run the configuration) conditionally.

use-package is entirely complementary to existing package system. But,
it suffers from bootstrap. It's obviously not possible to do

(use-package use-package
  :ensure t)

or configure use-package in any other way with use-package. Instead, you
have to do:

(require 'package)

(add-to-list 'package-archives
             '("melpa-stable" . "http://stable.melpa.org/packages/";) t)

(when (not (package-installed-p 'use-package))
    (package-install 'use-package))