cheat sheets.

=== Effective .emacs ===


--- Tip #0: Use Emacs 22 ------------------------------------------------------

Emacs 22 is super stable. About half of my .emacs file (before I cleaned it up)
was loading stuff that's now part of Emacs 22 and has autoloads.


--- Tip #1: Never quit Emacs --------------------------------------------------

Okay, this has nothing to do with your .emacs file, but I have to put it in
here. Just because your .emacs file should load quickly doesn't imply that you
should quit and restart all the time. Figure it out!


--- Tip #2: (require 'cl) -----------------------------------------------------

I put this at the top of my .emacs. It's a no-brainer. It adds in a ton of
compatibility with CL, so that you can just use the CL functions you know and
love (well, most of them, anyway), without a second thought.


--- Tip #3: Never LOAD, never REQUIRE -----------------------------------------

Your .emacs file shouldn't contain any calls to LOAD or REQUIRE (which are slow
and often cause errors on startup). The only possible exceptions are loading
files that contain nothing but autoloads (or similar stuff). How do you avoid
loads and requires? First try removing each call to LOAD or REQUIRE to see if
it's needed at all. Often (e.g., if you follow Tip #0) Emacs already has
autoloads in place for the library already (e.g., "cc-mode"). For other
libraries, where that's not true, put your own autoloads in your .emacs file.
For example, rather than load slime in my .emacs (so I can bind the F1 key to
SLIME-SELECTOR), instead I have:

(autoload 'slime-selector "slime" t)

The only call to LOAD in my .emacs file is for "erlang-start", but if you look
inside the file you can see it contains only autoloads (and morally equivalent
stuff). I also load the custom file, but that's different, see Tip #7. I don't
have a single call to REQUIRE (beyond that mandated by Tip #2).


--- Tip #4: Understand and use EVAL-AFTER-LOAD --------------------------------

Another reason why you might have strewn needless REQUIRE and LOAD calls
throughout your .emacs file is that you need to call a function from a specific
library. For example, let's say you want to set your default SQL database type
to MySQL:

(sql-set-product 'mysql)

If you put this in your .emacs, you'll get an error because the SQL library
isn't loaded so SQL-SET-PRODUCT isn't yet defined. But before you add a LOAD or
REQUIRE, stop! Instead do:

(eval-after-load "sql"
'(progn
(sql-set-product 'mysql)
;; any other config specific to sql
))

As the name suggests, this will defer calling that code until the SQL module is
actually loaded. This saves startup time and prevents errors!

--- Tip #5: Time your .emacs --------------------------------------------------

You really ought to know how much time it's taking to load your .emacs file. Use
the following in your .emacs:

(defvar *emacs-load-start* (current-time))

;; rest of your .emacs goes here

(message "My .emacs loaded in %ds" (destructuring-bind (hi lo ms) (current-time)
                             (- (+ hi lo) (+ (first *emacs-load-start*) (second
                             *emacs-load-start*)))))

After Emacs finishing initializing, you can switch to the *Messages* buffer and
see how much of that time was taken by loading your .emacs. Mine now contributes
less than one second!


--- Tip #6: Set background colors ---------------------------------------------

Don't just stand for the default colors! Set them to what you really want. In my
case I want a reverse video effect:

(set-background-color "black")
(set-face-background 'default "black")
(set-face-background 'region "black")
(set-face-foreground 'default "white")
(set-face-foreground 'region "gray60")
(set-foreground-color "white")
(set-cursor-color "red")


--- Tip #7: Separate custom file ----------------------------------------------

It's annoying to have your .emacs file modified by Emacs' "custom" library,
especially if you check in your .emacs to a source code control system such as
Subversion (which you should do) and synchronize it on multiple machines. Keep
those customizations in a separate file:

(setq custom-file "~/.emacs-custom.el")
(load custom-file 'noerror)

=== comments

Well, LOADs and REQUIREs are often slow (and often accomplish nothing, since
there are usually autoloads for "standard" functionality nowadays anyway) and
also a source of errors. For example, I run Emacs on 5 different machines, and
they don't all have the same libraries on them (I'm talking about the things
that aren't part of the Emacs 22 distribution, of course). Using a combination
of EVAL-AFTER-LOAD and AUTOLOAD instead of using LOAD means that unless I
actually try to use features that aren't available on a particular machine, I
won't get an error loading the library unless I actually try to use the feature.

---

Thanks! After eval-after-load-ing everything I could, I nearly halved my emacs
startup time!

At some point I'll go back and move each library's config to its own file and
just autoload all of those, but I have work to put off.

---


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SOURCE: http://a-nickels-worth.blogspot.com/2007/11/effective-emacs.html
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