#+TITLE: How to build an editor with Emacs Lisp
#+SEQ_TODO: TODO(t/!) NEXT(n/!) BLOCKED(b@/!) | DONE(d%) CANCELLED(c@/!) FAILED(f@/!)
#+TAGS: READER(r) MISC(m)
#+STARTUP: logdrawer logdone logreschedule indent content align constSI entitiespretty overview

* DONE Episode 1 - Introduction
CLOSED: [2022-01-09 Sun 19:03]
** What is it all about?
- Create an editor, development environment and Window Manager (yeah window manager) and ...
- GNU/Emacs is amazing
- Spread the joy
- Guide for contributors
- A guide for people who wants to learn some Lisp

** The Plan
- Parallel video series to *How to build a compiler with LLVM and MLIR*
- Git branches
- No live coding
- Start from Emacs and Jump to FG42
- Feel free to contribute

** FG42 and a bit of history
- It's my:
  + Editor/IDE
  + Email client
  + Window Manager
  + File Manager
  + Terminal Emulator
  + IRC client (at some point)
  + TODO manager
  + "Office suit" (air qoute)
  + ....
- Started on 2010 in a train
- I'm working on the V3
- Requirements
  + Emacs >= 27.1

- Website: https://fg42.org/
- Repository: https://devheroes.codes/FG42
- Website: https://lxsameer.com
- Email: lxsameer@gnu.org or lxsameer@lxsameer.com
* DONE Episode 2 - Survive on the first day
CLOSED: [2022-02-11 Fri 10:28]
** Why bother?
** Why GNU/Emacs?
*** People might say because of
- Org-mode
- LSP support
- Support for many many languages
- It's lightweight
- Tons of plugins
- ...
*** I'd say
- Coz it's a lisp environment with an editor attached to it
- Lisp is the difference
  + It's super easy to extend/hack emacs
  + In compare to other editors
- You can do pretty much whatever your like in ELisp
- It's like a framework for building an editor

** FAQ
*** What is the difference between Doom, Spacemacs, FG42 and ...?
Different editors based on Emacs
*** Which one should I use?
*** How to install Emacs packages?

** UI Basics & Basic Concepts
- Window
- Frame
- Mode line
- Buffers
- Mini buffer/Echo area
- Point
- Major mode
- Minor mode

** Basic Keybindings
How to read key bindings? Here is an example =C-x M-e 4=, it means press =x= key while
holding =Control= and then press =e= key while pressing down =Alt= and finally press =4=.

- Emacs tutorial =C-h t= (or https://www.gnu.org/software/emacs/tour/)
- Quit emacs =C-x C-c=
- Abort =C-g=
- Get Help =C-h= family
  + =C-h f=
  + =C-h v=
  + =C-h m=
  + =C-h k=
  + =C-h a=

- Run a command (function) =M-x=
- Visit a file =C-x C-f=
- Search in Buffer =C-s=
- Save buffer =C-x C-s=
- Select region =C-SPC=
- Copy =M-w=
- Cut(killing) =C-w=
- Paste(yanking) =C-y=
- Kill buffer =C-x k=
- Switch buffer =C-x b=
- Undo =C-/=
- Eval expression =C-x C-e=
- =describe-mode=
** Lisp basics
- Expressions everywhere
- Code a data structure
- Almost everything in Lisp evaluates to themselves except:
  + lists
  + Symbols
  + ...
- Lisp laws:
  1. Everything in Lisp is an expression and evaluation of an expression
     means replacing it with its value

  2. Almost everything in Lisp evaluates to themselves except:
     - Lists
     - Symbols
     - Quotes
     - ...
     -
 3. List evaluation
* Episode 3 - Lisp Basics
** FAQ:
- How to install Emacs?
  + Just make sure to have *Emacs >= 27.1*
- What's the routine to use Emacs ?
  + Don't use Emacs like how you use other Editors.
  + There is no limits(Almost).

- How evaluate forms?
  + *C-x C-e* at the end of any expression and anywhere
  + ielm
  + Batch mode

** So Fare:

*** Lisp rules:
1. Lisp is made of Expressions and they evaluate to a value.
2. All the expression types evaluates to themselves with some exceptions.
3. List evaluation

*** We will continue with Lisp basics for few episodes
** Variables
- How to define variables and constants
- Set the value of a variable
- Global and local scope
- Lexical bindings vs Dynamic bindings
  + =-*- lexical-binding: t; -*-=

** Functions
- How to define functions
- vs macros
- vs special forms