#+TITLE: Emacs Configuration
#+AUTHOR: Marc Pohling

* Personal Information

#+begin_src emacs-lisp
 (setq user-full-name "Marc Pohling"
       user-mail-address "marc.pohling@googlemail.com")
#+end_src


* Update config in a running config
Two options:
  - reload the open file: M-x load-file, then press twice to accept
    the default filename, which is the currently opened
  - Point at the end of any sexp and press C-x C-e


* Customize settings

Move the customize settings to its own file, instead of saving
customize settings in [[file:init.el][init.el]].

#+begin_src emacs-lisp
 (setq custom-file (expand-file-name "custom.el" user-emacs-directory))
 (load custom-file)
#+end_src


* Theme
** Material Theme
The [[https://github.com/cpaulik/emacs-material-theme][Material Theme]] comes in a dark and a light variant. Not too dark
to be strenious though.

#+begin_src emacs-lisp
 (use-package material-theme
     :if (window-system)
     :defer t
     :ensure t
     :init
     (load-theme 'material t)
 )
#+end_src


* Sane defaults
Sources for this section include [[https://github.com/magnars/.emacs.d/blob/master/settings/sane-defaults.el][Magnars Sveen]] and [[http://pages.sachachua.com/.emacs.d/Sacha.html][Sacha Chua]]

These functions are useful. Activate them.
#+begin_src emacs-lisp
 (put 'downcase-region 'disabled nil)
 (put 'upcase-region 'disabled nil)
 (put 'narrow-to-region 'disabled nil)
 (put 'dired-find-alternate-file 'disabled nil)
#+end_src
Answering just 'y' or 'n' should be enough.
#+begin_src emacs-lisp
 (defalias 'yes-or-no-p 'y-or-n-p)
#+end_src
Keep all backup and auto-save files in one directory
#+begin_src emacs-lisp
 (setq backup-directory-alist '(("." . "~/.emacs.d/backups")))
 (setq auto-save-file-name-transforms '((".*" "~/.emacs.d/auto-save-list/" t)))
#+end_src
UTF-8 please
#+begin_src emacs-lisp
 (setq locale-coding-system 'utf-8)
 (set-terminal-coding-system 'utf-8)
 (set-keyboard-coding-system 'utf-8)
 (set-selection-coding-system 'utf-8)
 (prefer-coding-system 'utf-8)
#+end_src

Avoid tabs in place of multiple spaces (they look bad in TeX)
and show empty lines
#+begin_src emacs-lisp
 (setq-default indent-tabs-mode nil)
 (setq-default indicate-empty-lines t)
#+end_src

Turn off blinking cursor
#+begin_src emacs-lisp
 (blink-cursor-mode -1)
#+end_src

Don't count two spaces after a period as the end of a sentence.
Just one space is needed
#+begin_src emacs-lisp
 (setq sentence-end-double-space nil)
#+end_src

Delete the region when typing, just like as we expect nowadays.
#+begin_src emacs-lisp
 (delete-selection-mode t)
#+end_src

Various stuff
#+begin_src emacs-lisp
 (show-paren-mode t)
 (column-number-mode t)

 (global-visual-line-mode)
 (diminish 'visual-line-mode)
 
 (setq uniquify-buffer-name-style 'forward)
#+end_src


* List buffers
Ibuffer is the improved version of list-buffers.
Make ibuffer the default buffer lister. [[http://ergoemacs.org/emacs/emacs_buffer_management.html][Source]]
#+begin_src emacs-lisp
 (defalias 'list-buffers 'ibuffer)
#+end_src

Also auto refresh dired, but be quiet about it. [[http://whattheemacsd.com/sane-defaults.el-01.html][Source]]
#+begin_src emacs-lisp
 (add-hook 'dired-mode-hook 'auto-revert-mode)
 (setq global-auto-revert-non-file-buffers t)
 (setq auto-revert-verbose nil)
#+end_src


* Recentf
#+begin_src emacs-lisp
 (use-package recentf
     :bind ("C-x C-r" . helm-recentf)
     :config
     (recentf-mode t)
     (setq recentf-max-saved-items 200)
 )
#+end_src


* Org Mode
** Installation
Although org mode ships with Emacs, the latest version can be installed externally. The configuration here follows the [[http://orgmode.org/elpa.html][Org mode ELPA Installation instructions.]]

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

To avoid problems executing source blocks out of the box. [[https://emacs.stackexchange.com/a/28604][Others have the same problem, too]]. The solution is to remove the .elc files form the package directory:

#+begin_src sh:
 var ORG_DIR=(let* ((org-v (cadr (split-string (org-version nil t) "@"))) (len (length org-v))) (substring org-v 1 (- len 2)))
 rm ${ORG_DIR}/*.elc
#+end_src

*** Org activation bindings
Set up some global key bindings that integrate with Org mode features

#+begin_src emacs-lisp
 (bind-key "C-c l" 'org-store-link)
 (bind-key "C-c c" 'org-capture)
 (bind-key "C-c a" 'org-agenda)
#+end_src

*** Org agenda
For a more detailed example [[https://github.com/sachac/.emacs.d/blob/83d21e473368adb1f63e582a6595450fcd0e787c/Sacha.org#org-agenda][see here]].

#+begin_src emacs-lisp
 (setq org-agenda-files
     (delq nil
         (mapcar (lambda (x) (and (file-exists-p x) x))
                 '("~/Archiv/Dokumente/Agenda"))
     )
 )
#+end_src

*** Org capture
#+begin_src emacs-lisp
 (bind-key "C-c c" 'org-capture)
 (setq org-default-notes-file "~/Archiv/Dokumente/Notizen/notes.org")
#+end_src


** Org Setup
Speed commands are a nice and quick way to perform certain actions while at the beginning of a heading. It's not activated by default.

See the doc for speed keys by checking out the documentation for speed keys in Org mode.

#+begin_src emacs-lisp
 (setq org-use-speed-commands t)
 (setq org-image-actual-width 550)
 (setq org-highlight-latex-and-related '(latex script entities))
#+end_src


** Org tags
The default value is -77, which is weird for smaller width windows. I'd rather have the tags align horizontally with the header.
45 is a good column number to do that.

#+begin_src emacs-lisp
 (setq org-tags-column 45)
#+end_src


** Org babel languages

#+begin_src emacs-lisp
 (org-babel-do-load-languages
'org-babel-load-languages
  '((python . t)
    (C . t)
    (calc . t)
    (latex . t)
    (java . t)
    (ruby . t)
    (lisp . t)
    (scheme . t)
    (shell . t)
    (sqlite . t)
    (js . t)))

 (defun my-org-confirm-babel-evaluate (lang body)
     "Do not confirm evaluation for these languages."
     (not (or (string= lang "C")
              (string= lang "java")
              (string= lang "python")
              (string= lang "emacs-lisp")
              (string= lang "sqlite"))))
 (setq org-confirm-babel-evaluate 'my-org-confirm-babel-evaluate)
#+end_src


** Org babel/source blocks
I like to have source blocks properly syntax highlighted and with the editing popup window staying within the same window so all the windows don't jump around. Also, having the top and bottom trailing lines in the block is a waste of space, so we can remove them

I noticed that fontification doesn't work with markdown mode when the block is indented after editing it in the org src buffer - the leading #s for headers don't get fontified properly because they apppear as Org comments. Setting ~org-src-preserve-identation~ makes things consistent as it doesn't pad source blocks with leading spaces

#+begin_src emacs-lisp
 (setq org-src-fontify-natively t
       org-src-window-setup 'current-window
       org-src-strip-leading-and-trailing-blank-lines t
       org-src-preserve-indentation t
       org-src-tab-acts-natively t)
#+end_src


* which-key
Greatly increases discovery of functions!
Click [[https://github.com/justbur/emacs-which-key][here]] for source and more info.
Info in Emacs: M-x customize-group which-key

#+begin_src emacs-lisp
 (use-package which-key
     :ensure t
     :diminish which-key-mode
     :config
     (which-key-mode)
     (which-key-setup-side-window-right-bottom)
     (which-key-setup-minibuffer)
     (setq which-key-idle-delay 0.5)
 )
#+end_src


* ivy / counsel / swiper

Ivy displays a window with suggestions for hotkeys and M-x

#+begin_src emacs-lisp
 (use-package ivy
     :ensure t
     :diminish
     (ivy-mode . "")                   ;; does not display ivy in the mode line
     :init
     (ivy-mode 1)
     :bind
     ("C-c C-r" . ivy-resume)
     :config
     (setq ivy-use-virtual-buffers t)  ;; recent files and bookmarks in ivy-switch-buffer
     (setq ivy-height 20)              ;; height of ivy window
     (setq ivy-count-format "%d/%d")   ;; current and total number
 )
#+end_src

Counsel replaces:
- M-x
- C-x C-f find-file
- C-c h f describe-function
- C-c h v describe-variable
- M-i     imenu

The find-file replacement is nicer to navigate

#+begin_src emacs-lisp
 (use-package counsel
     :ensure t
     :bind*                           ;; load counsel when pressed
     (("M-x"     . counsel-M-x)
      ("C-x C-f" . counsel-find-file)
      ("C-c h f" . counsel-describe-function)
      ("C-c h v" . counsel-describe-variable)
      ("M-i"     . counsel-imenu)
     )
 )
#+end_src

Swiper ivy-enhances isearch

#+begin_src emacs-lisp
 (use-package swiper
     :ensure t
     :bind
     (("C-s"     . swiper)
      ("C-c C-r" . ivy-resume)
     )
 )
#+end_src
 

* Programming
** Common things
List of plugins and settings which are shared between the language plugins

*** Company Mode
Complete Anything!

Activate company and make it react nearly instantly

#+begin_src emacs-lisp
 (use-package company
     :ensure t
     :config
     (add-to-list 'company-backends 'company-elisp)
     (setq company-minimum-prefix-length 2
           company-tooltip-align-annotation t
           company-tooltop-flip-when-above t
           company-show-numbers t)
     (setq company-idle-delay 0.1)
     (add-hook 'after-init-hook 'global-company-mode)
;;     (global-company-mode t)
 )
#+end_src

Addon to sort suggestions by usage

#+begin_src emacs-lisp
 (use-package company-statistics
     :ensure t
     :config
     (company-statistics-mode 1)
 )
#+end_src

Get a popup with documentation of the completion candidate.
I have to test if it even works.

#+begin_src emacs-lisp
 (use-package company-quickhelp
     :ensure t
     :config
     (company-quickhelp-mode 1)
 )
#+end_src

Maybe add [[https://github.com/hlissner/emacs-company-dict][company-dict]]? It's a dictionary based on major modes, plus it has Yasnippet integration.


** Python

Systemwide following packages need to be installed:
- virtualenv

The virtual environments need to have following modules installed:
- jedi
- epc
- flake8

Automatically start python-mode when opening a .py-file.
Not sure if python.el is better than python-mode.el.
See [[https://github.com/jorgenschaefer/elpy/issues/887][here]] for info about ~python-shell-completion-native-enable~.
The custom function is to run inferiour processes (do I really need that?), see [[https://emacs.stackexchange.com/questions/16361/how-to-automatically-run-inferior-process-when-loading-major-mode][here]].

#+begin_src emacs-lisp
 (use-package python
     :mode ("\\.py\\'" . python-mode)
     :interpreter ("python" . python-mode)
     :config
     (setq python-shell-completion-native-enable nil)
;;     (defun my/run-python ()
;;         (save-selected-window
;;             (switch-to-buffer-other-window (process-buffer (python-shell-get-or-create-process (python-shell-parse-command)))))
;;     )
;;     (add-hook 'python-mode-hook 'my/run-python)
 )
#+end_src

~TEST~ ELPY

begin_src emacs-lisp
 (use-package elpy
     :ensure t
;;     :pin elpy
     :config
     (elpy-enable)
     (add-hook 'python-mode-hook 'elpy-mode)
     (setq elpy-rpc-backend "jedi")
     (pyvenv-mode 1)
 )
end_src

Jedi is a backend for python autocompletion and needs to be installed on the server:
- pip install jedi
Code checks need to be installed, too:
- pip install flake8

#+begin_src emacs-lisp
 (use-package company-jedi
     :defer t
     :ensure t
     :config
     (setq jedi:environment-virtualenv (list (expand-file-name "~/Archiv/Programmierprojekte/Python/virtualenv/")))
     (add-hook 'python-mode-hook 'jedi:setup)
     (setq jedi:complete-on-dot t)
     (setq jedi:use-shortcuts t)
     (defun my/python-mode-hook()
         (add-to-list 'company-backends 'company-jedi))
     (add-hook 'python-mode-hook 'my/python-mode-hook)
 )
#+end_src

A wrapper to handle virtual environments.
I strongly recommend to install virtual environments on the terminal, not through this wrapper, but changing venvs is fine.

#+begin_src emacs-lisp
 (use-package virtualenvwrapper
     :ensure t
     :init
     (venv-initialize-interactive-shells)
     (venv-initialize-eshell)
     (setq venv-location "~/Archiv/Programmierprojekte/Python/virtualenv")
     (setq python-environment-directory venv-location)
     (add-hook 'venv-postmkvirtualenv-hook
               (lambda () (shell-command "pip install epc jedi")))
     (add-hook 'venv-postactivate-hook 'jedi:stop-server)
     (add-hook 'venv-postdeactivate-hook 'jedi:stop-server)
 )
#+end_src