[emacs] more background info

[~bandali/configs] / init.org

#+title: =aminb='s Literate Emacs Configuration
#+author: Amin Bandali
#+babel: :cache yes
#+property: header-args :tangle yes

* About
:PROPERTIES:
:CUSTOM_ID: about
:END:

This org file is my literate configuration for GNU Emacs, and is
tangled to [[./init.el][init.el]]. Packages are installed and managed using
[[https://github.com/emacscollective/borg][Borg]]. Over the years, I've taken inspiration from configurations of
many different people. Some of the configurations that I can remember
off the top of my head are:

- [[https://github.com/dieggsy/dotfiles][dieggsy/dotfiles]]: literate Emacs and dotfiles configuration, uses
  straight.el for managing packages
- [[https://github.com/dakra/dmacs][dakra/dmacs]]: literate Emacs configuration, using Borg for managing
  packages
- [[http://pages.sachachua.com/.emacs.d/Sacha.html][Sacha Chua's literate Emacs configuration]]
- [[https://github.com/dakrone/eos][dakrone/eos]]
- Ryan Rix's [[http://doc.rix.si/cce/cce.html][Complete Computing Environment]] ([[http://doc.rix.si/projects/fsem.html][about cce]])
- [[https://github.com/jwiegley/dot-emacs][jwiegley/dot-emacs]]: nix-based configuration
- [[https://github.com/wasamasa/dotemacs][wasamasa/dotemacs]]
- [[https://github.com/hlissner/doom-emacs][Doom Emacs]]

I'd like to have a fully reproducible Emacs setup (part of the reason
why I store my configuration in this repository) but unfortunately out
of the box, that's not achievable with =package.el=, not currently
anyway. So, I've opted to use Borg. For what it's worth, I briefly
experimented with [[https://github.com/raxod502/straight.el][straight.el]], but found that it added about 2 seconds
to my init time; which is unacceptable for me: I use Emacs as my
window manager (via EXWM) and coming from bspwm, I'm too used to
having fast startup times.

** Installation

To use this config for your Emacs, first you need to clone this repo,
then bootstrap Borg, tell Borg to retrieve package submodules, and
byte-compiled the packages. Something along these lines should work:

#+begin_src sh
git clone https://github.com/aminb/dotfiles ~/.emacs.d
cd ~/.emacs.d
make bootstrap-borg
make tangle-init
make bootstrap
make build
#+end_src

* Contents                                                   :toc_1:noexport:

- [[#about][About]]
- [[#header][Header]]
- [[#initial-setup][Initial setup]]
- [[#core][Core]]
- [[#post-initialization][Post initialization]]
- [[#footer][Footer]]

* Header
:PROPERTIES:
:CUSTOM_ID: header
:END:

** First line

#+begin_src emacs-lisp :comments none
;;; init.el --- Amin Bandali's Emacs config -*- lexical-binding: t ; eval: (view-mode 1)-*-
#+end_src

Enable =view-mode=, which both makes the file read-only (as a reminder
that =init.el= is an auto-generated file, not supposed to be edited),
and provides some convenient key bindings for browsing through the
file.

** License

#+begin_src emacs-lisp :comments none
;; Copyright (C) 2018  Amin Bandali <amin@aminb.org>

;; This program is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with this program.  If not, see <https://www.gnu.org/licenses/>.
#+end_src

** Commentary

#+begin_src emacs-lisp :comments none
;;; Commentary:

;; Emacs configuration of Amin Bandali, computer scientist and functional
;; programmer.

;; THIS FILE IS AUTO-GENERATED FROM `init.org'.
#+end_src

** Naming conventions

The conventions below were inspired by [[https://github.com/hlissner/doom-emacs][Doom]]'s conventions, found
[[https://github.com/hlissner/doom-emacs/blob/5dacbb7cb1c6ac246a9ccd15e6c4290def67757c/core/core.el#L3-L17][here]]. Naturally, I use my initials, =ab=, instead of =doom=.

#+begin_src emacs-lisp :comments none
;; Naming conventions:
;;
;;   ab-...   public variables or non-interactive functions
;;   ab--...  private anything (non-interactive), not safe for direct use
;;   ab/...   an interactive function; safe for M-x or keybinding
;;   ab:...   an evil operator, motion, or command
;;   ab|...   a hook function
;;   ab*...   an advising function
;;   ab@...   a hydra command
;;   ...!     a macro
#+end_src

* Initial setup
:PROPERTIES:
:CUSTOM_ID: initial-setup
:END:

#+begin_src emacs-lisp :comments none
;;; Code:
#+end_src

** Emacs initialization

I'd like to do a couple of measurements of Emacs' startup time. First,
let's see how long Emacs takes to start up, before even loading
=init.el=, i.e. =user-init-file=:

#+begin_src emacs-lisp
(defvar ab--before-user-init-time (current-time)
  "Value of `current-time' when Emacs begins loading `user-init-file'.")
(message "Loading Emacs...done (%.3fs)"
         (float-time (time-subtract ab--before-user-init-time
                                    before-init-time)))
#+end_src

Also, temporarily increase ~gc-cons-threshhold~ and
~gc-cons-percentage~ during startup to reduce garbage collection
frequency. Clearing the ~file-name-handler-alist~ seems to help reduce
startup time as well.

#+begin_src emacs-lisp
(defvar ab--gc-cons-threshold gc-cons-threshold)
(defvar ab--gc-cons-percentage gc-cons-percentage)
(defvar ab--file-name-handler-alist file-name-handler-alist)
(setq gc-cons-threshold (* 400 1024 1024)  ; 400 MiB
      gc-cons-percentage 0.6
      file-name-handler-alist nil
      ;; sidesteps a bug when profiling with esup
      esup-child-profile-require-level 0)
#+end_src

Of course, we'd like to set them back to their defaults once we're
done initializing.

#+begin_src emacs-lisp
(add-hook
 'after-init-hook
 (lambda ()
   (let ((elapsed (float-time (time-subtract (current-time)
                                             ab--before-user-init-time))))
     (message "Loading %s...done (%.3fs) [after-init]"
              user-init-file elapsed))
   (setq gc-cons-threshold ab--gc-cons-threshold
         gc-cons-percentage ab--gc-cons-percentage
         file-name-handler-alist ab--file-name-handler-alist)))
#+end_src

Increase the number of lines kept in message logs (the =*Messages*=
buffer).

#+begin_src emacs-lisp
(setq message-log-max 20000)
#+end_src

Optionally, we could suppress some byte compiler warnings like below,
but for now I've decided to keep them enabled. See documentation for
~byte-compile-warnings~ for more details.

#+begin_src emacs-lisp
;; (setq byte-compile-warnings
;;       '(not free-vars unresolved noruntime lexical make-local))
#+end_src

** Package management

*** No =package.el=

I can do all my package management things with Borg, and don't need
Emacs' built-in =package.el=. Emacs 27 lets us disable =package.el= in
the =early-init-file= (see [[https://git.savannah.gnu.org/cgit/emacs.git/commit/?id=24acb31c04b4048b85311d794e600ecd7ce60d3b][here]]).

#+begin_src emacs-lisp :tangle early-init.el
(setq package-enable-at-startup nil)
#+end_src

But since Emacs 27 isn't out yet (Emacs 26 is just around the corner
right now), and even when released it'll be long before most distros
ship in their repos, I'll still put the old workaround with the
commented call to ~package-initialize~ here anyway.

#+begin_src emacs-lisp
(setq package-enable-at-startup nil)
;; (package-initialize)
#+end_src

*** Borg

#+begin_quote
Assimilate Emacs packages as Git submodules
#+end_quote

[[https://github.com/emacscollective/borg][Borg]] is at the heart of package management of my Emacs setup. In
short, it creates a git submodule in =lib/= for each package, which
can then be managed with the help of Magit or other tools.

#+begin_src emacs-lisp
(setq user-init-file (or load-file-name buffer-file-name)
      user-emacs-directory (file-name-directory user-init-file))
(add-to-list 'load-path
             (expand-file-name "lib/borg" user-emacs-directory))
(require 'borg)
(borg-initialize)
#+end_src

*** =use-package=

#+begin_quote
A use-package declaration for simplifying your .emacs
#+end_quote

[[https://github.com/jwiegley/use-package][use-package]] is an awesome utility for managing and configuring
packages (in our case especially the latter) in a neatly organized way
and without compromising on performance.

#+begin_src emacs-lisp
(require 'use-package)
(if nil				    ; set to t when need to debug init
    (setq use-package-verbose t
          use-package-expand-minimally nil
          use-package-compute-statistics t
          debug-on-error t)
  (setq use-package-verbose nil
        use-package-expand-minimally t))
#+end_src

*** Epkg

#+begin_quote
Browse the Emacsmirror package database
#+end_quote

Epkg provides access to a local copy of the [[https://emacsmirror.net][Emacsmirror]] package
database, low-level functions for querying the database, and a
=package.el=-like user interface for browsing the available packages.

#+begin_src emacs-lisp
(use-package epkg
  :defer t)
#+end_src

** No littering in =~/.emacs.d=

#+begin_quote
Help keeping ~/.emacs.d clean
#+end_quote

By default, even for Emacs' built-in packages, the configuration files
and persistent data are all over the place. Use =no-littering= to help
contain the mess.

#+begin_src emacs-lisp
(use-package no-littering
  :demand t
  :config
  (savehist-mode 1)
  (add-to-list 'savehist-additional-variables 'kill-ring)
  (save-place-mode 1)
  (setq auto-save-file-name-transforms
        `((".*" ,(no-littering-expand-var-file-name "auto-save/") t))))
#+end_src

** Custom file (=custom.el=)

I'm not planning on using the custom file much, but even so, I
definitely don't want it mixing with =init.el=. So, here; let's give
it it's own file. While at it, treat themes as safe.

#+begin_src emacs-lisp
(use-package custom
  :no-require t
  :config
  (setq custom-file (no-littering-expand-etc-file-name "custom.el"))
  (when (file-exists-p custom-file)
    (load custom-file))
  (setf custom-safe-themes t))
#+end_src

** Better =$PATH= handling

Let's use [[https://github.com/purcell/exec-path-from-shell][exec-path-from-shell]] to make Emacs use the =$PATH= as set up
in my shell.

#+begin_src emacs-lisp
(use-package exec-path-from-shell
  :defer 1
  :init
  (setq exec-path-from-shell-check-startup-files nil)
  :config
  (exec-path-from-shell-initialize)
  ;; while we're at it, let's fix access to our running ssh-agent
  (exec-path-from-shell-copy-env "SSH_AGENT_PID")
  (exec-path-from-shell-copy-env "SSH_AUTH_SOCK"))
#+end_src

** Server

Start server if not already running. Alternatively, can be done by
issuing =emacs --daemon= in the terminal, which can be automated with
a systemd service or using =brew services start emacs= on macOS. I use
Emacs as my window manager (via EXWM), so I always start Emacs on
login; so starting the server from inside Emacs is good enough for me.

See [[https://www.gnu.org/software/emacs/manual/html_node/emacs/Emacs-Server.html#Emacs-Server][Using Emacs as a Server]].

#+begin_src emacs-lisp
(use-package server
  :config (or (server-running-p) (server-mode)))
#+end_src

* Core
:PROPERTIES:
:CUSTOM_ID: core
:END:

** Defaults

*** Smaller fringe

Might want to set the fringe to a smaller value, especially if using
EXWM. I'm fine with the default for now.

#+begin_src emacs-lisp
;; (fringe-mode '(3 . 1))
#+end_src

*** Disable disabled commands

Emacs disables some commands by default that could persumably be
confusing for novice users. Let's disable that.

#+begin_src emacs-lisp
(setq disabled-command-function nil)
#+end_src

*** Kill-ring

Save what I copy into clipboard from other applications into Emacs'
kill-ring, which would allow me to still be able to easily access it
in case I kill (cut or copy) something else inside Emacs before
yanking (pasting) what I'd originally intended to.

#+begin_src emacs-lisp
(setq save-interprogram-paste-before-kill t)
#+end_src

*** Minibuffer

#+begin_src emacs-lisp
(setq enable-recursive-minibuffers t
      resize-mini-windows t)
#+end_src

*** Lazy-person-friendly yes/no prompts

Lazy people would prefer to type fewer keystrokes, especially for yes
or no questions. I'm lazy.

#+begin_src emacs-lisp
(defalias 'yes-or-no-p #'y-or-n-p)
#+end_src

*** Startup screen and =*scratch*=

Firstly, let Emacs know that I'd like to have =*scratch*= as my
startup buffer.

#+begin_src emacs-lisp
(setq initial-buffer-choice t)
#+end_src

Now let's customize the =*scratch*= buffer a bit. First off, I don't
need the default hint.

#+begin_src emacs-lisp
(setq initial-scratch-message nil)
#+end_src

Also, let's use Text mode as the major mode, in case I want to
customize it (=*scratch*='s default major mode, Fundamental mode,
can't really be customized).

#+begin_src emacs-lisp
(setq initial-major-mode 'text-mode)
#+end_src

Inhibit the buffer list when more than 2 files are loaded.

#+begin_src emacs-lisp
(setq inhibit-startup-buffer-menu t)
#+end_src

I don't really need to see the startup screen or echo area message
either.

#+begin_src emacs-lisp
(advice-add #'display-startup-echo-area-message :override #'ignore)
(setq inhibit-startup-screen t
      inhibit-startup-echo-area-message user-login-name)
#+end_src

*** More useful frame titles

Show either the file name or the buffer name (in case the buffer isn't
visiting a file). Borrowed from Emacs Prelude.

#+begin_src emacs-lisp
(setq frame-title-format
      '("" invocation-name " - "
        (:eval (if (buffer-file-name)
                   (abbreviate-file-name (buffer-file-name))
                 "%b"))))
#+end_src

*** Backups

Emacs' default backup settings aren't that great. Let's use more
sensible options. See documentation for the ~make-backup-file~
variable.

#+begin_src emacs-lisp
(setq backup-by-copying t
      version-control t)
#+end_src

** Packages

The packages in this section are absolutely essential to my everyday
workflow, and they play key roles in how I do my computing. They
immensely enhance the Emacs experience for me; both using Emacs, and
customizing it.

*** [[https://github.com/emacscollective/auto-compile][auto-compile]]

#+begin_src emacs-lisp
(use-package auto-compile
  :demand t
  :config
  (auto-compile-on-load-mode)
  (auto-compile-on-save-mode)
  (setq auto-compile-display-buffer               nil
	auto-compile-mode-line-counter            t
	auto-compile-source-recreate-deletes-dest t
	auto-compile-toggle-deletes-nonlib-dest   t
	auto-compile-update-autoloads             t)
  (add-hook 'auto-compile-inhibit-compile-hook
            'auto-compile-inhibit-compile-detached-git-head))
#+end_src

*** TODO [[https://github.com/Kungsgeten/ryo-modal][ryo-modal]]

#+begin_quote
Roll your own modal mode
#+end_quote

*** [[https://github.com/ch11ng/exwm][EXWM]] (window manager)

#+begin_src emacs-lisp
(use-package exwm
  :demand t
  :config
  (require 'exwm-config)
  (exwm-config-default)
  (require 'exwm-systemtray)
  (exwm-systemtray-enable)
  (require 'exwm-randr)
  (exwm-randr-enable))
#+end_src

*** [[https://orgmode.org/][Org mode]]

#+begin_quote
Org mode is for keeping notes, maintaining TODO lists, planning
projects, and authoring documents with a fast and effective plain-text
system.
#+end_quote

In short, my favourite way of life.

#+begin_src emacs-lisp
(setq org-src-tab-acts-natively t
      org-src-preserve-indentation nil
      org-edit-src-content-indentation 0)
#+end_src

*** [[https://magit.vc/][Magit]]

#+begin_quote
It's Magit! A Git porcelain inside Emacs.
#+end_quote

Not just how I do git, but /the/ way to do git.

#+begin_src emacs-lisp
(use-package magit
  :defer t
  :bind (("s-g"     . magit-status)
	 ("C-x g"   . magit-status)
         ("C-x M-g" . magit-dispatch-popup))
  :config
  (magit-add-section-hook 'magit-status-sections-hook
                          'magit-insert-modules
                          'magit-insert-stashes
                          'append))
#+end_src

*** [[https://github.com/abo-abo/swiper][Ivy]] (and friends)

#+begin_quote
Ivy - a generic completion frontend for Emacs, Swiper - isearch with
an overview, and more. Oh, man!
#+end_quote

There's no way I could top that, so I won't attempt to.

**** Ivy

#+begin_src emacs-lisp
(use-package ivy
  :bind
  (:map ivy-minibuffer-map
        ([escape] . keyboard-escape-quit)
        ("C-j"    . ivy-next-line)
        ("C-k"    . ivy-previous-line)
        ([S-up]   . ivy-previous-history-element)
        ([S-down] . ivy-next-history-element)
        ("DEL"    . ivy-backward-delete-char))
  :config
  (ivy-mode 1))
#+end_src

**** Swiper

#+begin_src emacs-lisp
(use-package swiper
  :bind (([remap isearch-forward]  . swiper)
	 ([remap isearch-backward] . swiper)))
#+end_src

**** Counsel

#+begin_src emacs-lisp
(use-package counsel
  :defer 1.5
  :bind (([remap execute-extended-command] . counsel-M-x)
         ([remap find-file] . counsel-find-file)
         ("s-r"     . counsel-recentf)
         :map minibuffer-local-map
	 ("C-r" . counsel-minibuffer-history))
  :config
  (counsel-mode 1)
  (defalias 'locate #'counsel-locate))
#+end_src

* Borg's =layer/essentials=

TODO: break this giant source block down into individual org sections.

#+begin_src emacs-lisp
(use-package dash
  :config (dash-enable-font-lock))

(use-package diff-hl
  :config
  (setq diff-hl-draw-borders nil)
  (global-diff-hl-mode)
  (add-hook 'magit-post-refresh-hook 'diff-hl-magit-post-refresh t))

(use-package dired
  :defer t
  :config (setq dired-listing-switches "-alh"))

(use-package eldoc
  :when (version< "25" emacs-version)
  :config (global-eldoc-mode))

(use-package help
  :defer t
  :config (temp-buffer-resize-mode))

(progn ;    `isearch'
  (setq isearch-allow-scroll t))

(use-package lisp-mode
  :config
  (add-hook 'emacs-lisp-mode-hook 'outline-minor-mode)
  (add-hook 'emacs-lisp-mode-hook 'reveal-mode)
  (defun indent-spaces-mode ()
    (setq indent-tabs-mode nil))
  (add-hook 'lisp-interaction-mode-hook #'indent-spaces-mode))

(use-package man
  :defer t
  :config (setq Man-width 80))

(use-package paren
  :config (show-paren-mode))

(use-package prog-mode
  :config (global-prettify-symbols-mode)
  (defun indicate-buffer-boundaries-left ()
    (setq indicate-buffer-boundaries 'left))
  (add-hook 'prog-mode-hook #'indicate-buffer-boundaries-left))

(use-package recentf
  :demand t
  :config (add-to-list 'recentf-exclude "^/\\(?:ssh\\|su\\|sudo\\)?:"))

(use-package savehist
  :config (savehist-mode))

(use-package saveplace
  :when (version< "25" emacs-version)
  :config (save-place-mode))

(use-package simple
  :config (column-number-mode))

(progn ;    `text-mode'
  (add-hook 'text-mode-hook #'indicate-buffer-boundaries-left))

(use-package tramp
  :defer t
  :config
  (add-to-list 'tramp-default-proxies-alist '(nil "\\`root\\'" "/ssh:%h:"))
  (add-to-list 'tramp-default-proxies-alist '("localhost" nil nil))
  (add-to-list 'tramp-default-proxies-alist
               (list (regexp-quote (system-name)) nil nil)))

(use-package undo-tree
  :config
  (global-undo-tree-mode)
  (setq undo-tree-mode-lighter ""))
#+end_src

* Post initialization
:PROPERTIES:
:CUSTOM_ID: post-initialization
:END:

Display how long it took to load the init file.

#+begin_src emacs-lisp
(message "Loading %s...done (%.3fs)" user-init-file
         (float-time (time-subtract (current-time)
                                    ab--before-user-init-time)))
#+end_src

* Footer
:PROPERTIES:
:CUSTOM_ID: footer
:END:

#+begin_src emacs-lisp :comments none
;;; init.el ends here
#+end_src