Emacs Lisp (nano) cheat sheet

Invoke function (C-x C-e to evaluate)

(f x0 x1)
(f x0 x1 x2)

Function definition

(defun my-fun (x0 x1)
  "function description"
  (+ x0 x1))

Lambda function

(setq my-f (lambda (x y) (+ x y)))
(funcall my-f 1 2)

Setting variables, with quote is the name of the variable
(setq x y) is equivalent to (set (quote x) y)

(setq name "nautilus")
(setq name value)
'x ;; is the name of x, not the value (like the pointer in C)
'(a b c)  ;; is a list
(setq x '(0 1 2 3)) ;; x is a list

Emacs, latex, and all that

GNU Emacs is great, superfun

You can play a lot with things like latex, and org-mode, and coding in emacs
I use emacs in windows and linux systems

Windows 10 WSL

I was used to the windows version of emacs 25 in windows 10, but WSL is a supernice tool, thus I recently switched to WSL Ubuntu 20.04, and installed emacs27 via the PPA repository. You may install the APP ubuntu 20.04 in Windows Store. See this post

In windows 10 new need a good X10 server for opening windows, I found that X410 works nicely (it is not freeware)

You need to modify your .bashrc and add

DISPLAY=localhost:0
export DISPLAY

The windows filesystem in the ubuntu WSL terminal is automatically mounted in /mnt/c/Users/

To install emacs27 in ubuntu 20.04 WSL

sudo add-apt-repository ppa:kelleyk/emacs
sudo apt update
sudo apt install emacs27

Ubuntu 20.04

Same as above, works fine

My emacs configuration

As for many Linux things, the nice feature in emacs and all that is that you can easily configure anything. The problem is that you may become addicted in continuously changing the settings, because you do not like the window size, the font, etc. The good news is that this is also true in emacs!

To configure emacs you can either change the file .emacs, whic you can put or find in your home directory. Or you may change the file .emacs.d/init.el where .emacs.d is a config directory that is also in the home. The two methods are exclusive, meaning that either you use .emacs, or .emacs.d/init.el. I prefer to used .emacs.d/init.el as it is more recent.

For example, if you want to change the font, you have to put the following line in .emacs.d/init.el

(set-face-attribute 'default (selected-frame) :height 100)

This may seem weird, as it is not something like fontsize=12, but it is a glimpse into the supersmart world of Lisp. Indeed emacs is written in Lisp, a proper Lisp, the “emacs-lisp” and that is the reason why emacs is so cool.

to be continued

emacs, auctex, Sumatra.pdf in Windows 10

On Windows 10 Pro

Install MiKTeX from https://miktex.org/

Download emacs zip file in the GNU mirror. I have chosen in http://mirror.lihnidos.org/GNU/ftp/gnu/emacs/windows/ the file in the folder emacs-26 http://mirror.lihnidos.org/GNU/ftp/gnu/emacs/windows/emacs-26/emacs-26.3-x86_64.zip

Unzip the emacs file in some folder for example Downloads folder, you will have a folder with name emacs-26.1-x86.4

Inside this emacs folder, click on runemacs

Now emacs is running, but you need to install auctex and Sumatra.pdf. You may create a shortcut to runemacs in the application bar by right clicking on it

To install auctex open emacs, then “M+x package-install auctex” and hit return

M+x package-install auctex

Sumatra.pdf enables to open multiple windows with the same pdf file. Acrobat blocks the compilation if the pdf is open.

Install Sumatra.pdf from https://www.sumatrapdfreader.org

Sumatra.pdf exe file will be in “C:\Program Files\SumatraPDF”

C:\Program Files\SumatraPDF

Now you need to configure emacs for using Sumatra.pdf, this is done by modifying the .emacs file

The .emacs file is the main configuration file for emacs

You find the .emacs file in the folder “C:\Users\<USER>\AppData\Roaming”

C:\Users\YourUserNameHere\AppData\Roaming

This is a hidden folder, you need to enable showing hidden folder in windows explorer (go to options in the folder menu)

Open .emacs and add the lines at the end of the file and save

(setq TeX-PDF-mode t)
(setq TeX-source-correlate-mode t)
(setq TeX-source-correlate-method 'synctex)
(setq TeX-view-program-list
'(("Sumatra PDF" ("\"C:/Program Files/SumatraPDF/SumatraPDF.exe\" -reuse-instance"
   (mode-io-correlate " -forward-search %b %n ") " %o"))))

(eval-after-load 'tex
 '(progn
   (assq-delete-all 'output-pdf TeX-view-program-selection)
   (add-to-list 'TeX-view-program-selection '(output-pdf "Sumatra PDF")))
 )
(server-start)

Now you are set to run auctex in emacs with forward search and Sumatra.pdf