dotfiles/emacs/.emacs.d/init.el

;; __        __    _  __      _       _       _ _         _
;; \ \      / /__ | |/ _| ___( )___  (_)_ __ (_) |_   ___| |
;;  \ \ /\ / / _ \| | |_ / _ \// __| | | '_ \| | __| / _ \ |
;;   \ V  V / (_) | |  _|  __/ \__ \ | | | | | | |_ |  __/ |
;;    \_/\_/ \___/|_|_|  \___| |___/ |_|_| |_|_|\__(_)___|_|


;; Disable file name handler for performance during startup
(defvar wolfe/file-name-handler-alist file-name-handler-alist)
(setq file-name-handler-alist nil
      ;; Set garbage collect high to speed up startup
      gc-cons-threshold most-positive-fixnum
      gc-cons-percentage 0.6
      ;; Ignore advice warnings
      ad-redefinition-action 'accept)

(add-hook 'emacs-startup-hook
          (lambda () (setq gc-cons-threshold 16777216
                      gc-cons-percentage 0.1
                      file-name-handler-alist wolfe/file-name-handler-alist
                      ad-redefinition-action 'warn)))

(require 'package)
;; Setup package sources
(setq package-archives '(("gnu" . "http://elpa.gnu.org/packages/")
                         ("melpa" . "http://melpa.org/packages/")
                         ("org" . "http://orgmode.org/elpa/")))
(setq package-enable-at-startup nil)
(setq package-pinned-packages '((use-package . "melpa")))
(package-initialize)

;; Bootstrap use-package
(unless (package-installed-p 'use-package)
  (package-refresh-contents)
  (package-install 'use-package))
(require 'use-package)
(setq use-package-always-ensure t)

;; Use latest org before calling babel
(use-package-pin-package 'org "org")
(use-package org
  :ensure org-plus-contrib)

(defun init/tangle-section-canceled ()
  "Return t if the current section header was CANCELED, else nil."
  (save-excursion
    (if (re-search-backward "^\\*+\\s-+\\(.*?\\)?\\s-*$" nil t)
        (string-prefix-p "CANCELED" (match-string 1))
      nil)))

(defun init/tangle-config-org (orgfile elfile)
  "This function will write all source blocks from =config.org= into
=config.el= that are ...

- not marked as :tangle no
- have a source-code of =emacs-lisp=
- doesn't have the todo-marker CANCELED"
  (let* ((body-list ())
         (gc-cons-threshold most-positive-fixnum)
         (org-babel-src-block-regexp   (concat
                                        ;; (1) indentation                 (2) lang
                                        "^\\([ \t]*\\)#\\+begin_src[ \t]+\\([^ \f\t\n\r\v]+\\)[ \t]*"
                                        ;; (3) switches
                                        "\\([^\":\n]*\"[^\"\n*]*\"[^\":\n]*\\|[^\":\n]*\\)"
                                        ;; (4) header arguments
                                        "\\([^\n]*\\)\n"
                                        ;; (5) body
                                        "\\([^\000]*?\n\\)??[ \t]*#\\+end_src")))
    (with-temp-buffer
      (insert-file-contents orgfile)
      (goto-char (point-min))
      (while (re-search-forward org-babel-src-block-regexp nil t)
        (let ((lang (match-string 2))
              (args (match-string 4))
              (body (match-string 5))
              (canc (init/tangle-section-canceled)))
          (when (and (string= lang "emacs-lisp")
                     (not (string-match-p ":tangle\\s-+no" args))
                     (not canc))
            (add-to-list 'body-list body)))))
    (with-temp-file elfile
      (insert (format ";;; -*- lexical-binding: t -*-\n" orgfile))
      (apply 'insert (reverse body-list)))
    (message "Wrote %s ..." elfile)))

(let ((orgfile (concat user-emacs-directory "README.org"))
      (elfile (concat user-emacs-directory "README.el")))
  (when (or (not (file-exists-p elfile))
            (file-newer-than-file-p orgfile elfile))
    (init/tangle-config-org orgfile elfile))
  (load-file elfile))