#+TITLE: Emacs Configuration
#+AUTHOR: Camden Dixie O'Brien
#+ATTR_LATEX: :float t

Shout out to Harry R. Schwartz; A whole bunch of this config
(including the idea of embeddeding the lot in an Org document) is
yanked from [[https://github.com/hrs/dotfiles][his dotfiles repo]].

The rest of this config grabs packages via =use-package=, so that
needs to be set up to install them if they aren't already.

#+begin_src emacs-lisp
  (require 'use-package-ensure)
  (setq use-package-always-ensure t)
#+end_src

* UI

  The start-up message gets pretty annoying, so disable that.

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

  The default window size is just a little too small for my taste.

  #+begin_src emacs-lisp
    (when window-system (set-frame-size (selected-frame) 90 48))
  #+end_src

  And I like a little more line spacing than default.

  #+begin_src emacs-lisp
    (setq-default line-spacing 0.2)
  #+end_src

  Also, the menu-, tool- and scroll-bar are ugly, take up space and I
  don't use them.

  #+begin_src emacs-lisp
    (menu-bar-mode -1)
    (tool-bar-mode -1)
    (scroll-bar-mode -1)
  #+end_src

** Colour Scheme

   Currently using =spacemacs-theme='s light variant, but I prefer a pure
   white background to the off-white it has by default.

   #+begin_src emacs-lisp
     (use-package spacemacs-theme
       :defer t)
     (setq spacemacs-theme-custom-colors
           '((bg1 . "#ffffff")
             (comment-bg . "#ffffff")))
     (load-theme 'spacemacs-light t)
   #+end_src

** Font

   I am addicted to programming ligatures but Fira Code (my preferred
   ligature font) requires some hackery to display properly; this is
   defined in [[file:fira-code-mode/fira-code-mode.el][fira-code-mode.el]] so first we load that.

   #+begin_src emacs-lisp
     (add-to-list 'load-path "/home/cdo/.emacs.d/fira-code-mode")
     (require 'fira-code-mode)
   #+end_src

   And then make sure that mode is enabled for any =prog-mode= buffer.

   #+begin_src emacs-lisp
     (add-hook 'prog-mode-hook 'fira-code-mode)
   #+end_src

* Org-mode

  I use a couple non-standard bits and pieces, but not a whole bunch. I
  really like the =<s= to insert a source block thing (which was
  deprecated); =org-tempo= brings that back.

  #+begin_src emacs-lisp
    (use-package org
      :ensure org-plus-contrib
      :config
      (require 'org-tempo))
  #+end_src

** Agenda

   Set up a keybinding for [[help:org-agenda][org-agenda]] and tell it where to look. I
   have a bunch of org documents making up a sort of wiki which I keep
   under [[file:~/exo][~/exo]].

   #+begin_src emacs-lisp
     (define-key global-map (kbd "C-c a") 'org-agenda)
     (setq org-agenda-files
           (directory-files-recursively "~/exo" "\.org$"))
   #+end_src

   Log when tasks were marked =DONE=, just for graphs.

   #+begin_src emacs-lisp
     (setq org-log-done t)
   #+end_src

   I often want to see TODO items that aren't scheduled to decide on
   something to do (if I've already done all the scheduled things), so
   it's nice for [[help:org-agenda][org-agenda]] to have an option for that.

   #+begin_src emacs-lisp
     (setq org-agenda-custom-commands
           '(("u" "Unscheduled tasks" tags "-SCHEDULED={.+}/!+TODO")))
   #+end_src

** Source Blocks

   Pressing tab inside a source block should indent appropriately for its
   language.

   #+begin_src emacs-lisp
     (setq org-src-tab-acts-natively t)
   #+end_src

   =babel= lets us evaluate Org documents containing source blocks!
   I've left the enabling of this for most languages to the section
   for that language, but I'll add Emacs Lisp here.

   #+begin_src emacs-lisp
     (org-babel-do-load-languages
      'org-babel-load-languages
      '((emacs-lisp . t)))
   #+end_src

   By default trying to execute a source block prompts you, which is
   super annoying since I'm realistically not going to try to run any
   code from Org documents I haven't written, so that needs
   disabling. You can do that by setting [[help:org-confirm-babel-evaluate][org-confirm-babel-evaluate]] to
   =nil=.

   #+begin_src emacs-lisp
     (setq org-confirm-babel-evaluate nil)
   #+end_src

** Exporting

*** HTML

	=htmlize= is needed for decent HTML exporting, and there is no need
	for all that stuff at the bottom.

	#+begin_src emacs-lisp
      (use-package htmlize)
      (setq org-html-postamble nil)
	#+end_src

*** LaTeX

	Use =minted= (LaTeX package) to do syntax highlighting in code blocks:

	#+begin_src emacs-lisp
      (add-to-list 'org-latex-packages-alist '("" "minted"))
      (setq org-latex-listings 'minted)
	#+end_src

	=minted= actually calls =pygments= through the shell, which =pdflatex=
	doesn't like; you have to tell it not to worry, and that everything is
	going to be OK.

	#+begin_src emacs-lisp
      (setq org-latex-pdf-process
            '("xelatex -shell-escape -interaction nonstopmode -output-directory %o %f"
              "xelatex -shell-escape -interaction nonstopmode -output-directory %o %f"
              "xelatex -shell-escape -interaction nonstopmode -output-directory %o %f"))
	#+end_src

	Also, I don't like Emacs' built-in PDF viewer, so open PDFs in [[https://mupdf.com/][MuPDF]] instead:

	#+begin_src emacs-lisp
      (eval-after-load "org"
        '(progn
           (setcdr (assoc "\\.pdf\\'" org-file-apps) "mupdf %s")))
	#+end_src

* Start up

  Org is better suited as scratch space than Funamental, I'd say.

  #+begin_src emacs-lisp
    (setq initial-major-mode 'org-mode)
    (setq initial-scratch-message "")
  #+end_src

  I always want [[file:~/exo/index.org][~/exo/index.org]] to open on start-up, as that's where I
  keep links to whatever I happen to be doing at any given time; one
  does that by setting [[help:initial-buffer-choice][initial-buffer-choice]]

  #+begin_src emacs-lisp
    (setq initial-buffer-choice "~/exo/index.org")
  #+end_src

* Magit

  =magit= is truly a wonderful creation! Only deviations from defaults
  here are a keybinding for =magit-status= and a maximum length for the
  summary line of commit messages (after which the excess is
  highlighted).

  #+begin_src emacs-lisp
    (use-package magit
      :bind
      ("C-x g" . magit-status)
      :config
      (setq git-commit-summary-max-length 50))
  #+end_src

* Language Integrations

  Generally, 8-character-wide tabs are not my thing.

  #+begin_src emacs-lisp
    (setq-default tab-width 4)
    (setq-default basic-offset 4)
  #+end_src

  And generally indenting with spaces is more common, so make that the default:

  #+begin_src emacs-lisp
    (setq-default indent-tabs-mode nil)
  #+end_src

** C

   For C, I like to indent with tabs and align with spaces: this
   behaviour is provided by =smart-tabs-mode=. 

   #+begin_src emacs-lisp
     (use-package smart-tabs-mode)
     (smart-tabs-insinuate 'c)
   #+end_src

   I'll generally format my code in BSD style but I also use
   =clang-format= a lot, so I have a keybinding to run that.

   #+begin_src emacs-lisp
     (setq c-default-style "bsd")
     (use-package clang-format)
     (add-hook 'c-mode-hook
               (lambda ()
                 (define-key c-mode-map (kbd "C-M-f")
                   'clang-format-buffer)))
   #+end_src

   Meson is my build system of choice for C, but I also use CMake a lot.

   #+begin_src emacs-lisp
     (use-package meson-mode)
     (use-package cmake-mode)
   #+end_src

** Haskell

   My workflow with Haskell is very REPL-based, so I always want
   =interactive-haskell-mode= on.

   #+begin_src emacs-lisp
     (use-package haskell-mode)
     (require 'haskell-interactive-mode)
     (add-hook 'haskell-mode-hook 'interactive-haskell-mode)
   #+end_src

   And, of course, that REPL needs to be taking advantage of parallelism!

   #+begin_src emacs-lisp
     (require 'haskell-process)
     (set-variable 'haskell-process-args-ghci
                   '("-threaded" "+RTS" "-N8" "-RTS"))
   #+end_src

** Idris

   The only thing to change from the defaults here is to add a more
   convenient way to case-split.

   #+begin_src emacs-lisp
     (use-package idris-mode)
     (add-hook 'idris-mode-hook
               (lambda ()
                 (define-key idris-mode-map (kbd "C-c SPC")
                   'idris-case-split)))
   #+end_src

** Rust

   I never really use Rust without Cargo, so always turn on the minor
   mode for Cargo in Rust buffers.

   #+begin_src emacs-lisp
     (use-package rust-mode)
     (use-package cargo)
     (add-hook 'rust-mode-hook 'cargo-minor-mode)
   #+end_src

** Lisps

*** Racket
   Get =racket-mode= for some Racket-specific things, like searching documentation

   #+begin_src emacs-lisp
     (use-package racket-mode)
   #+end_src

*** Common Lisp
   Use SLIME and Quicklisp for Common Lisp (SBCL), with a convenient
   binding for =slime-selector=

   #+begin_src emacs-lisp
     (use-package slime)
     (setq inferior-lisp-program "sbcl")
     (global-set-key (kbd "C-c s") 'slime-selector)
     (load (expand-file-name "~/quicklisp/slime-helper.el"))
   #+end_src

*** Paredit
   =paredit= is generally very useful for balancing parenthesis so we
   want that turned on for all the lisps. Additionally, it's nice to have
   an entire expression highlighted when the cursor is on one of its
   enclosing parens.

   #+begin_src emacs-lisp
     (use-package paredit)
     (setq lispy-mode-hooks
           '(emacs-lisp-mode-hook
             lisp-mode-hook
             racket-mode-hook
             scheme-mode-hook))
     (dolist (hook lispy-mode-hooks)
       (add-hook hook (lambda ()
                        (setq show-paren-style 'expression)
                        (paredit-mode))))
   #+end_src

* Music Player

  I use MPD because it is clearly the best way to play music; sometimes
  it's nice to control it from Emacs, so I use MPDel for that.

  #+begin_src emacs-lisp
    (use-package mpdel
      :config
      (mpdel-mode))
  #+end_src

* RSS Feeds

  Using Newsticker, because it's included in Emacs. All I have to do
  here is add in all the feeds and add a global keybinding for
  =newsticker-show-news=. For some reason, I had to set both
  =newsticker-url-list-defaults= and =newsticker-url-list= to get rid
  of the EmacsWiki feed it has by default.

  #+begin_src emacs-lisp
    (use-package newsticker
      :bind
      ("C-x M-r" . newsticker-show-news))
    (setq newsticker-url-list-defaults nil)
    (setq newsticker-url-list
          '(("Sean Carroll's Mindscape Podcast"
             "https://www.patreon.com/rss/seanmcarroll?auth=xZISWBuCvZ1rKXy547HnRXQVyBIscY1P"
             nil
             3600)
            ("Corecursive"
             "https://link.chtbl.com/corecursive?platform=rss"
             nil
             3600)
            ("The Titanium Physicists Podcast"
             "http://titaniumphysics.libsyn.com/rss"
             nil
             3600)))
  #+end_src

  Also I want Newsticker to download enclosed files so I set
  =newsticker-new-item-functions= to contain the provided
  =newsticker-download-enclosures= function.

  #+begin_src emacs-lisp
    (setq newsticker-new-item-functions
          '(newsticker-download-enclosures))
  #+end_src