Deal with Emacs

From where I talk ?

Who I am ?

• Mainly a geek guy
• Research Engineer at Univ. Paris 7 Diderot
• • Post-Doc Católica (Chile)
  • Post-Doc Univ. Liège (hi Berty!)
  • PhD at ONERA Toulouse

simon.tournier@univ-paris-diderot.fr

https://github.com/zimoun

My life

• 2006-2010: Vim user… and happy!

• 2011 New Year Resolutions: Switch to Emacs (video)

  \(\Rightarrow\) because the sysadmin showed me crazy stuff

  && he helped me to start.

I am only an enthusiast user, not a guru

My typical use-cases

• Edit multiple languages: Python, Julia, C/C++, (Fortran), R, Shell, \(\LaTeX\), Haskell, Scheme, etc.
• Git (pull, commit, merge)
• Organize my tasks and log them
• Write docs and few papers, compose "workflow"

(defun ask-at-point (&optional i-know)
  "Feel free to ask everything."
  (interactive "P")
  (if i-know (message "Quick Answer.")
   (browse-url
    (concat "https://www.ddg.gg/?q=emacs+" (thing-at-point 'symbol)))))

Contents

1. Quick Intro to Emacs
2. How to configure: use-package
3. Quick Demo:
   • \(\LaTeX\)
   • Python
4. Goodies
5. Org-mode: markdown on steroid
6. A bit of Emacs Lisp (power to the people)
   • just for fun: mini fem solver inside Emacs

What Emacs is ?

Definition

Emacs is a User Interface (UI) to manipulate text

• Editor
• IDE for a lot of languages (CEDET, SLIME, Geiser, EIN)
• Mail Reader, Mail Reader, RSS Reader, etc.
• Extensible Lisp machine?
• Windows Manager?
• OS? :-)

Theorem

All what X is able, Emacs does it too.

Proof: Let as an exercise after this presentation.

Corollary

(counter) Example

Start Emacs

How you feel when you start

Weirdness comes from Oldness

Initial release: 1976; 42 years ago (timeline)

• Macintosh : 1984

  First mass-market computer with GUI and mouse

• Windows 1.0: 1985

  (claim starting dev. GUI in 1981)

A window is not a window

• "Frames" are to Emacs what windows are to everything else
• "Windows" are subdivisions of frames

• "Buffer" hold the content of a file

  "Open a file" means open a buffer that "visits" that file

Control C is not Copy

C-x C-f means

press Control and x then Control and f

M-x means press Alt and x

Ah Bon?

Keep Calm and Practise

Some basics

Ressources

• https://www.gnu.org/software/emacs/tour/
• https://www.tuteurs.ens.fr/unix/editeurs/emacs.html
• http://ergoemacs.org/emacs/emacs.html

sachachua.com/blog

sachachua.com/blog 2

Refcard

https://www.gnu.org/software/emacs/refcards/pdf/refcard.pdf

A demo speaks better than words

@simon: check your cheatsheet :-)

Summary

"Habit is habit, and not to be flung out of the window by any man, but coaxed downstairs a step at a time." – Mark Twain

Remember

• Keyboard driven (source of power)
• Command is first class citizen
• one command should be binded to one Keymap

Remember 2

I DO NOT recommand CUA-mode (windows-like shortcuts)

Remember 3

Muscle one small step after another

How to configure

The configuration is driven by

$HOME/.emacs.d/init.el

Basics

Basics 1

Set variables

;; to see the life in colours
(global-font-lock-mode 1)
;; to remove the icons bar
(tool-bar-mode 0)
;; what?!? who use the latteral bar to scroll ? :-)
(scroll-bar-mode 0)

Set other variables

;; remove the initial starting message
(setq inhibit-startup-message t)

;; delete the *scratch* initial message
(setq initial-scratch-message nil)

@simon: quick demo-it

Basics 2

Conditional set

;; remove the menu when inside terminal
(if (display-graphic-p)
    (menu-bar-mode 1)
  (menu-bar-mode 0))

Rename commands

;; simplify the question-answer process
(defalias 'yes-or-no-p 'y-or-n-p)

;; M-x mode-* instead of the long name
(defalias 'mode-whitespace 'whitespace-mode)
(defalias 'mode-highlight 'global-hl-line-mode)

;; change the default file manager
(defalias 'list-directory 'dired)

Basics 3

Bind

;; set global shortcuts
(global-set-key [?\C-k] 'kill-whole-line)
(global-set-key [?\C-$] 'ispell-region)

;; special binding for specific mode (here dired)
(define-key dired-mode-map (kbd "E") 'dired-toggle-read-only))

Hook

;; delete dirty spaces
(add-hook 'before-save-hook 'delete-trailing-whitespace)

A journey of a thousand miles begins with a single step

Packages

"The coolest feature of Emacs is all the available packages." – Doctor Who, the coolest nerd ever

Repos: ELPA and MELPA

Built-in since Emacs 24

(require 'package)
(setq package-enable-at-startup nil)
(add-to-list 'package-archives
             ;; `use-package' is not in ELPA, as many more ;-)
             '("melpa" . "http://melpa.org/packages/"))
(add-to-list 'package-archives
               ;; Add org-plus-contrib
               '("org" . "http://orgmode.org/elpa/"))
(package-initialize)

M-x package-list-packages

use-package

;; boostrap `use-package' by John Wiegley
(unless (package-installed-p 'use-package)
  (package-refresh-contents)
  (package-install 'use-package))
;; load it
(require 'use-package)

Example:

;; change the default file manager
(use-package dired
  :defer t
  :init
  (defalias 'list-directory 'dired)
  :config
  (define-key dired-mode-map (kbd "E") 'dired-toggle-read-only))

use-package 2

;; example of Julia configuration
(use-package ess
  :ensure t
  :defer t
  ;; :init                                  ; example with non-standard loc.
  ;; (setq inferior-julia-program
  ;;    "/Applications/Julia-0.6.app/Contents/Resources/julia/bin/julia")
  :mode (("\\.jl\\'" . ess-julia-mode))
  :defines ess-indent-offset            ; silent warning
  :config
  (require 'ess-julia)
  (require 'ess-utils)
  (setq ess-eval-visibly-p nil)
  (setq ess-use-eldoc'script-only))

Yes, it's awesome!

Two live Examples

@simon: do not forget to: sh config-me.sh

@simon: do not forget to turn-on command-log-mode :-)

latex-mode

# apt-get install aspell

python-mode

# apt-get install virtualenv ipython
$ pip install jedi epc pylint --user

More features (demo)

• Dired: file manager / directory editor
• EDiff: diff, merge files
• Magit: A Git porcelain
• EShell/term: yes litterally LIVE inside Emacs ;-)
• minor modes: whitespace-mode, glasses-mode, etc.
• find-grep, regular expression
• Remote files with TRAMP (edit file through ssh)
• Helm / Company
• …

Another killer feature: Org-mode

org-mode is…

"Awesome!" – John Kitchin (video)

• Markup language (see the backstage of this presentation)
• Note-taking utility
• TODO lists maintainer
• Planner, agenda
• Tables editor
• Helper to manage your projects (CEO explains his experience)
• included by default since Emacs 22 (2006)

Org is vast…

… start small!

"Don't try to set up the 'final' task managing system from the start. Because you have no idea yet what your system should look like. […] Start by creating and managing a small TODO list and then develop your own system as the needs arises." – Carsten Dominik (creator of org)

My experience

• Learn a couple of its capabilities
• Integrate them into your workflow
• You’ll find yourself thinking, "Hum?, it would be nice if I could X"
• Then check the manual, browse the web

… and, in fact, Org can do X

Demo

table and \(\LaTeX\)

• Write table with Org-mode (easy!)
• Export to .tex: C-c C-e C-b l l (body only)
• Use \input{}

(or epxort to buffer C-c C-e C-b l L and copy/paste)

DEMO!

makefile

all: doc.tex table1.tex table2.tex
        pdflatex doc.tex

%.tex: %.org
         emacs -batch -q $< --eval="(org-latex-export-to-latex nil nil t t)"

clean:
        -rm table?.tex
        -rm doc.{aux,log}

Ressources

• Org for beginners
• A tutorial/blog
• Google Tech Talk by Carsten Dominik (video)
• Original Paper (2012)
• Getting Started with Org-mode by New-York Emacs meetup (video)
• An implementation: Org-mode + GTD

Computational Document / Reproducible workflow

"Buzzword – What'chu talkin' 'bout, Willis?" – Arnold

• Org-Babel
• An Effective Git And Org-Mode Based Workflow For Reproducible Research
• Choosing your Workflow Applications
• Scimax by John Kitchin
• Emacs + Org-mode + Python = reproducible research (video)

Emacs Lisp

Lisp? Really?!?

Lisp is (Lots of ((Irritating, Spurious) (Parentheses)))

Lisp? tell me more…

First appeared 1958; 60 years ago

"A bad workman blames his tools." – Barack Obama

"Another language is a new life." – Persian proverb

"Learn a language, and you will avoid a war." – Arab proverb

Hacker (Paul Graham) citing Hacker (Eric S. Raymond): More here, here or here.

Finally, the truly serious hacker should consider learning Lisp:

Lisp is worth learning for the profound enlightenment experience you will have when you finally get it; that experience will make you a better programmer for the rest of your days, even if you never actually use Lisp itself a lot.

This is the same argument you tend to hear for learning Latin.

More here, here or here.

True!

Old pot, good jam

• Julia uses lisp (parser; try: julia --lisp) and lot of concepts (metaprogramming)

  See Julia: to Lisp or not to Lisp? (video)

• R is rooted in lisp

• Hy: lisp-flavored Python or python-flavored Lisp ? (video)
• GNU Guix: a transactional package manager fully reproducible; Supported by INRIA Bordeaux.
• Clojure: Java-world (JVM)
• Common Lisp:
  • Maxima a Computer Algebra System
  • Dimitri Fontaine rewrote PostgreSQL loader
• AutoLisp: AutoCAD

Emacs Lisp (ELisp) Ressources

• https://www.gnu.org/software/emacs/manual/eintr.html
• http://ergoemacs.org/emacs/elisp.html

• https://learnxinyminutes.com/docs/fr-fr/elisp-fr/

  by Bastien Guerry (Org-mode maintainer)

• Emacs Lisp Dev. Tips by John Wiegley (GNU Emacs maintainer) (video)

Basics

;; work with parenthesis
(show-paren-mode 1)       ; highlight matching parens
(electric-pair-mode 1)    ; open-close parens

• Start REPL

  M-x ielm

• Eval in mini-buffer: M-:

• Buffer with M-x emacs-lisp-mode

  C-x C-e

  end of S-expression

Basics 1

;; Declare variable
(setq x 1)

;; Compute (infix)
(+ x 42)
(* x 4.2)

;; List (linked)
(setq ll (list 1 2 3 4))
;; First element (head)
(car ll)
;; Rest (tail)
(cdr ll)
;; Concatenate lists
(append ll (list 11 22 33 44 55) (list "a" "bb" "ccc"))

Basics 2

Function

(defun hello-world (name)
  "Simply Hello World function.

Do stuff.
And other stuff.
The argument name provides a name to helloing."
  (message "Hello World: %s!" name))

Anonymous function

(lambda (name)
  (message "Hello: %s!" name))

Call/Apply a function: (hello-world "Dude")

Basics 3

(defun ask-at-point (&optional i-know)
  "Feel free to ask everything."
  (interactive "P")
  (if i-know (message "Quick Answer.")
   (browse-url
    (concat "https://www.ddg.gg/?q=emacs+" (thing-at-point 'symbol)))))

All the Lisp power at your fingertips

Emacs is just a Lisp machine

• Few built-in functions coded in C

  C-h f list or car, cdr, etc.

• And lot of Emacs Lisp ones

  C-h f ibuffer or find-file, dired, org, etc.

Read manual then read code on ELPA and MELPA

e.g., eshell

MIT museum

Simple functions

Upcase a word

(defun eg/upcase-word ()
  "Change from any word to UPPERCASE."
  (interactive)
  (let ((beg (progn
               (backward-word)
               (point)))
        (end (progn
               (forward-word)
               (point))))
        (upcase-region beg end)))

Next!

(global-set-key (kbd "M-u") 'my/upcase-word)

(defun eg/downcase-word ()
  "Change from any word to DOWNCASE."
  (interactive)
  (let ((beg (progn
               (backward-word)
               (point)))
        (end (progn
               (forward-word)
               (point))))
        (downcase-region beg end)))

Pattern ?

Refactor

(defun eg/change-case-word (fun)
  "Generic function to change the case of a word.

When the `point' is somewhere in word, first get the `backward-word'
position, second get the `forward-line' position, and last apply FUN
to these both."
  (interactive)
  (let ((beg (progn
               (backward-word)
               (point)))
        (end (progn
               (forward-word)
               (point))))
        (funcall fun beg end)))

Simple, isn't?

(defun eg/capitalize-word ()
  "Remap of `capitalize-word'."
  (interactive)
  (eg/change-case-word 'capitalize-region))

(defun eg/upcase-word ()
  "Remap of `upcase-word'."
  (interactive)
  (eg/change-case-word 'upcase-region))

(defun eg/downcase-word ()
  "Remap of `downcase-word'."
  (interactive)
  (eg/change-case-word 'downcase-region))

;; add quick bindings to the new nice functions
(global-set-key (kbd "M-c") 'eg/capitalize-word)
(global-set-key (kbd "M-u") 'eg/upcase-word)
(global-set-key (kbd "M-l") 'eg/downcase-word)

Count Words

Tutorial from VSCode to extend it

https://code.visualstudio.com/docs/extensions/example-word-count

Come on! It is not simpler than X.

(me: javascript is aweful)

Hum?

M-=

or

M-x count-words-region

Ok, do naive way!

(defun eg/count-words-region (start end)
  "Count words in the selected region.

Worse than `count-words-region'."
  (interactive "r")
  (let ((count-words->how-many 0))
    (goto-char start)
    (while (< (point) end)
      (if (forward-word 1)
          (setq count-words->how-many (1+ count-words->how-many))))

    (message "Region has %d words." count-words->how-many)
    count-words->how-many))

M-x eg/count-words-region

mini-fem solver with ELisp

Let only consider:

• list and the 4 arithmitic operations on integers and floats
• functions and recurcivity

\[\cos(x) = \textrm{real}~ \sum_n \frac{ix}{n!}\]

Demo

see https://github.com/zimoun/elfem1

A bit of elisp history

• Richard Stallman (father of GNU Emacs) speaks about Lisp
• Guy Steele (co-"father" of Emacs) still shares insights (video)
• Stefan Monnier (prev. maint. of GNU Emacs) exposes internals

–

• Guile Emacs tries to replace internals by Scheme
• REmacs reimplements internals with Rust (instead of C)

ELisp is not truly a Lisp?

Facts

• ELisp is Lisp-2 not Lisp-1
• No Tail Call Optimization
• Lexical scoping introduced lately (Emacs 24 2012)
• Foreign Function Interface (FFI) with Emacs 25 (2014)
• Concurrency introduced with Emacs 26 (2018)
• Simple Garbage Collector (mark&sweep)
• and more that I do not understand

What Emacs is ?

Start now!

Alternative Reality

• Emacs Prelude
• Spacemacs
• ErgoEmacs
• Emacs Bootstrap
• Viper \(\longrightarrow\) Evil
• Starter Kit
• Scimax

Key of Success

• Master a tool needs large amount of work

  think all the maths you learn before complete non-trivial proofs

• Master a tool is not easy; otherwise it is a lie

  think nunchaku practise to be as efficient as Bruce Lee

Why computing tools should be different ?

Be good at something is long

My personal conclusion

Why flamewar editor ?

• Our daily life is interacting with computers
• We are all differently wired
• Cognition is not straightforward

Editor should be freedom, not constraint and pain.

• Editor must help you to get things done
• Emacs pays off … for me

… because Emacs is the best! ;-)

Happy end?

Emacs is first at productive procrastination :-)