How I Emacs And So Can You: Packages

In the first post we looked at some basic usage and navigation, and set up use-package so we can easily add community packages to our Emacs installation.

Breathing Room

I think I go a little overboard with this, but every time one of my use-package declarations goes over a single line, I like to pull it out to its own file. That way I just have one line to comment/uncomment in init.el to activate/deactivate a package. To set this up, create a directory inside .emacs.d - I just called mine .emacs.d/lisp. We can ensure it gets evaluated by adding the following to init.el:

;; Pull in ./lisp/*
(add-to-list 'load-path (expand-file-name "lisp" user-emacs-directory))

Now any whatever.el elisp file we put in this directory will be visible to init.el.

The Emacs ecosystem is big, and there are multiple solutions and sets of solutions for any given problem. I like to keep mine pretty minimal, this is just the set that works for me - I do urge you to explore! The packages used in this set, notably, are not the same set that Spacemacs is based around. When you do your own research, it sorta-kinda comes down to helm & friends vs. ivy/swiper/counsel - this is the ivy route. I intentionally wanted to try something different from what I had gotten to know via Spacemacs, but it shouldn't be taken as a value judgement at all. I've enjoyed using both greatly.

These are completion engines. Remember the last post, when we forgot C-x C-s but then still miraculously knew it was save-buffer? With ivy, you'd be able to just hit M-x and then frantically start typing save and ivy will find everything it possibly could be. It will even helpfully show you the assigned key combination for a given command if there is one. Pretty damn handy with a tool as vast as Emacs! It's a personal always-on concierge.

Ivy/Counsel/Swiper

That's as good a place to start as any. Ivy is the main event here, and counsel and swiper are ivy-imbued versions of common commands and file search, respectively. Create a file called init-ivy.el:

;;; #init-ivy.el
;;; Commentary:
;;; http://oremacs.com/swiper/#installation
;;; https://sam217pa.github.io/2016/08/30/how-to-make-your-own-spacemacs/#fnref:3
;;; https://writequit.org/denver-emacs/presentations/2017-04-11-ivy.html#fnr.2
;;; Code:
(use-package ivy
  :diminish (ivy-mode . "")
  :init (ivy-mode 1) ; globally at startup
  :config
  (setq ivy-use-virtual-buffers t)
  (setq ivy-height 20)
  (setq ivy-count-format "%d/%d "))
(provide 'init-ivy)
;;; init-ivy.el ends here.

In this same file, I also set up counsel. This package overrides some built-in Emacs commands with more user friendly versions. Add this above the final comment:

;; Override the basic Emacs commands
(use-package counsel
  :bind* ; load when pressed
  (("M-x"     . counsel-M-x)
   ("C-s"     . swiper)
   ("C-x C-f" . counsel-find-file)
   ("C-x C-r" . counsel-recentf)  ; search for recently edited
   ("C-c g"   . counsel-git)      ; search for files in git repo
   ("C-c j"   . counsel-git-grep) ; search for regexp in git repo
   ("C-c /"   . counsel-ag)       ; Use ag for regexp
   ("C-x l"   . counsel-locate)
   ("C-x C-f" . counsel-find-file)
   ("<f1> f"  . counsel-describe-function)
   ("<f1> v"  . counsel-describe-variable)
   ("<f1> l"  . counsel-find-library)
   ("<f2> i"  . counsel-info-lookup-symbol)
   ("<f2> u"  . counsel-unicode-char)
   ("C-c C-r" . ivy-resume)))     ; Resume last Ivy-based completion

Don't worry too too much about memorizing everything here right off the bat - it will be here when you need it. For a while I had an index card with a few of the most handy ones sitting on my desk. In the last post we covered the "save" action, which was a whole keypress more than you're probably used to - this is because C-s is reserved for searching for text in the given file. Check out the video demo.

Interlude: Wait, There Totally Are Modes

Well, yes, but they're not Vim modes! In Emacs, a mode determines how Emacs semantically understands the text in the current buffer. These fall into two categories, major and minor - each buffer has one major mode, and can have multiple minor modes. A major mode might be something like clojure-mode - this text is only Clojure code, not some other type of code as well, but could have ivy-mode and spellcheck-mode enabled as well, because that functionality can stack.

Alright, now that init-ivy.el has been added to lisp/, we can add it to init.el:

(require 'init-ivy)

That's it! Evaluating that require expression with C-x C-e will read our new file and set up Ivy for us.

Flycheck

Another package I love is flycheck, which provides on the fly syntax checking. It has indicators for problematic lines, squiggly underlines, and pop-up tooltips - all the trappings of a modern syntax checker. This declaration is simpler:

;;; lisp/init-flycheck.el
(use-package flycheck
  :init (global-flycheck-mode))
(provide 'init-flycheck)

And in init.el:

(require 'init-flycheck)

Some languages will require special setup, but most things will just work out of the box.

Company

A perfect complement to flycheck-mode is company-mode, which provides text-completion. As you type, it will make suggestions. You can scroll through them with M-n and M-p, and use the enter key to select. There are more ways to interact with it as well - peep the docs for deets.

In lisp/init-company.el:

(use-package company
  :config
  (add-hook 'after-init-hook 'global-company-mode))
(provide 'init-company)

And of course (require 'init-company) in init.el. Now we're starting to feel like a real IDE!

which-key

This is probably my favorite of the bunch. Ivy is giving us some nice completions, but you still need to know where to start - it's not great for discovering what's available. Which-key will pop up a window when you begin a command listing everything available. In our save-buffer example, when you type the first C-x, you'll get a big pane detailing every combination available after C-x, with the combo and the command name. This is how I find new combos to learn, and it's great for jogging your memory.

My init-which-key.el:

(use-package which-key
  :init
  (which-key-mode)
  :config
  (which-key-setup-side-window-right-bottom)
  (setq which-key-sort-order 'which-key-key-order-alpha
    which-key-side-window-max-width 0.33
    which-key-idle-delay 0.05)
  :diminish which-key-mode)

(provide 'init-which-key)

Tweak these to your liking, these settings work for me. Of course, don't forget (require 'init-which-key) in init.el!

Smartparens

This minor mode helps manage your parentheses. It has a number of facilities for manipulating parenthetical expressions - a huge help no matter what programming language you use.

lisp/init-smartparens.el:

(use-package smartparens
  :config
  (require 'smartparens-config)
  (add-hook 'lisp-mode-hook #'smartparens-strict-mode))
(provide 'init-smartparens)

I've added a hook that activates an even stricter version when I'm in a specific minor mode - this is also something you'll need to tweak for yourself! I actually also use smartparents-strict-mode in rust-mode - we'll get to the langauge-specific stuff later.

By now you know the drill for getting it into init.el!

Neotree

This is my last general package. Neotree is a habit I picked up from Vim - it shows a graphical overview of the directory tree that you can use to switch between files. Another nicety that IDEs feel like they should have - though for the most part I find myself invoking C-x C-f or C-x b to navigate around in a project.

lisp/init-neotree.el:

(use-package neotree
  :init
  (require 'neotree)
  :config
  (setq neo-theme (if (display-graphic-p) 'icons 'arrow))
  (setq neo-smart-open t)
  )
(provide 'init-neotree)

I lied - that was the second to last. I also use find-file-in-project.

(use-package find-file-in-project)

Keybindings

The next order of business is setting up your own keybindings. We can use global-set-key for this. The first one I set is the key to activate neotree - add this to your init.el:

(global-set-key [f8] 'neotree-project-dir)

To enable this behavior, I have the following snippet stolen from the emacs wiki placed in lisp/bl-fns.el to facilitate NeoTree attempting to use the git project root when it opens:

(defun neotree-project-dir ()
  "Open NeoTree using the git root."
  (interactive)
  (let ((project-dir (ffip-project-root))
    (file-name (buffer-file-name)))
    (if project-dir
    (progn
      (neotree-dir project-dir)
      (neotree-find file-name))
      (message "Could not find git project root."))))

(provide 'bl-fns)

Pretty easy, right? Now the F8 key will toggle the NeoTree window. Cool. Another keybinding I add for myself that I find useful is this:

(global-set-key (kbd "C-c q") (lambda ()
                       (interactive)
                   (other-window -1)))

The kbd macro lets you define combos using the handy shorthand. This combo, C-c q, will switch back to the previous active window. I generally only have two or three open and find myself using this one a lot.

I also like this shorthand for company-complete:

(global-set-key (kbd "C-c h") 'company-complete)

Language-specific packages

Clojure

For clojure, I use CIDER:

;; init-clojure.el
(use-package clojure-mode)
(use-package cider)
(provide 'init-clojure)

CIDER is a whole can of worms in and of itself - I'll come back to that in a separate post sometime!

Rust

Rust has a little more going on to set it up with flycheck and cargo and everything:

;; init-rust.el
(use-package rust-mode)
(use-package flymake-rust)
(use-package racer)
(use-package company)
(use-package cargo
  :config
  (add-hook 'rust-mode-hook 'cargo-minor-mode))
(use-package flycheck-rust)
(with-eval-after-load 'rust-mode
  (add-hook 'flycheck-mode-hook #'flycheck-rust-setup))
(provide 'init-rust)

To be completely honest, Rust was my biggest driver in migrating toward VSCode - Rust in Emacs is fantastic, Rust in VSCode is unparalleled. The above works great, but I just can't in good faith recommend this setup over using the RLS from VSCode.

Some More

Forth, JavaScript/HTML/CSS, and Reason/OCaml I use with zero config:

(use-package forth-mode)
(use-package js2-mode)
(use-package reason-mode)
(use-package web-mode)
(use-package ocp-indent)

And....that's all I got for ya! This set of packages provides a complete multi-language IDE without much bloat.

To update your installed packages, run M-x list-packages - this will refresh the latest package list. Then just type U (shift-u) to upgrade any that are outdated.