hackweek-emacs/README.org

* How To Use

#+begin_src sh :results output scalar
cp -r <USB_MOUNT> ~/.emacs.d
chown -R <YOUR_USER> ~/.emacs.d
# ln -sf <THIS_REPO> ~/.emacs.d
#+end_src

* Introduction

*"Original" EMACS:*
- 1976
- David A. Moon & Guy L. Steele Jr.
- Set of macros for the TECO editor (char based editor)

*Gosling Emacs:*
- 1981
- James Gosling (the Java® guy)

*GNU Emacs:*
- 1984
- Richard Stallman aka. [[http://stallman.org/saint.html][Saint IGNUcius]] /(saint in the Church of Emacs)/

*Latest Release*: Emacs 30.1
*Released:* February, 2025

Emacs uses ~emacs-lisp~:
- lisp dialect
- functional (not pure though)
- specially developed to configure Emacs

** Variables

#+begin_src emacs-lisp :results output scalar
(defvar my/var nil "My very own variable")
(setq my/var "Hey Emacs!")
(print my/var)
;; There are more... (setq-local, setq-default)
#+end_src

#+RESULTS:
: "
: \"Hey Emacs!\"
: "

** Functions

#+begin_src emacs-lisp :results output scalar
(defun test ()
  "Docstring"
  (interactive)
  (print my/var))

(test)
#+end_src

#+begin_src emacs-lisp :results output scalar
(defun more (a b &optional c d &rest e)
  (interactive)
  ; 'a 'b 'c 'd '(...)
  (print (concat a b c d (mapconcat #'identity e ""))))

(more "1" "2" "3" "4" "5" "6" "7")
(more "1" "2" "3")
#+end_src

#+RESULTS:
: "
: \"1234567\"
:
: \"123\"
: "

#+begin_src emacs-lisp :results output scalar
(defun print-name (&rest args)
  (interactive)
  (let ((first (plist-get args :first))
        (last (or (plist-get args :last) "?")))
    (princ last)
    (when first
      (princ ", ")
      (princ first))))

(print-name :first "Philip" :last "B1")
#+end_src

#+RESULTS:
: "B1, Philip"

** Let Bindings

#+begin_src emacs-lisp :results output scalar
(defun another-test (a b)
  "Multiplies `A' times `B' and adds them afterwards"
  (interactive)
  (let* ((x a)
         (y (* x b)))
    (+ x y)))

(print (another-test 2 4))
#+end_src

#+RESULTS:
: "
: 10
: "

** Hooks

#+begin_src emacs-lisp :results output scalar
(defun my/fun () (message "Emacs is cool!"))
(add-hook 'after-save-hook #'my/fun)
;; (remove-hook 'after-save-hook 'my/fun)
#+end_src

** Package Management & Configuration

*Package Manager*
- https://github.com/radian-software/straight.el

#+begin_src emacs-lisp :results output scalar
; Standard is package.el
(straight-use-package 'nix-mode)
#+end_src

#+RESULTS:
: ""

*Configuration Macro*
- https://github.com/jwiegley/use-package

#+begin_src emacs-lisp :results output scalar
(straight-use-package 'use-package)

;; Macro that provides syntactic sugar
(use-package color-moccur
  ;; Creates autoloads for these commands
  ;; Defers loading of the module until command is used
  :commands (isearch-moccur isearch-all)
  ;; Keybindings
  :bind (("M-s O" . moccur)
         :map isearch-mode-map
         ("M-o" . isearch-moccur)
         ("M-O" . isearch-moccur-all))
  ;; Before package is loaded
  :init
  (setq isearch-lazy-highlight t)
  ;; After package is loaded
  :config
  (use-package moccur-edit))
#+end_src

** Tour de Emacs Config

.emacs.d/
├── early-init.el
├── init.el
└── cnf/
    ├── app
    └── lang

** Tasks
*** Keybinding

- Create a new keybinding for the ~emacs-lisp-mode~ that executes ~eval-last-sexp~ with the binding ~SPC x e~ while in ~normal~ mode

**** Possible Solution

#+begin_src emacs-lisp :results output scalar
(my-leader
  :keymaps 'emacs-lisp-mode-map
  :states 'normal
  "x" '(:ignore t :which-key "Eval")
  "x e" 'eval-last-sexp
  "x b" 'eval-buffer)
#+end_src

*** Package

- Install a new package using straight, e.g. ~swiper~ (or something else)

**** Possible Solution

#+begin_src emacs-lisp :results output scalar
(straight-use-package 'swiper)
#+end_src