this is a Clojure-friendly emacs config

If you're new to emacs, check out this introductory tutorial!

Installing

1. Close Emacs.
2. Delete ~/.emacs or ~/.emacs.d if they exist. (Windows users, your emacs files will probably live in C:\Users\your_user_name\AppData\Roaming\. So, for example, you would delete C:\Users\jason\AppData\Roaming\.emacs.d.) This is where Emacs looks for configuration files, and deleting these files and directories will ensure that you start with a clean slate.
3. Download the Emacs configuration zip file and unzip it. Its contents should be a folder, emacs-for-clojure-book1. Run mv path/to/emacs-for-clojure-book1 ~/.emacs.d.

Then open Emacs. The first time you start, it will take a few minutes, because it needs to download and install around fifty packages. You will see some warnings pop up, but they are only style suggestions for the packages being loaded.

Prerequisites

Since you're working in Clojure, we assume you have it and its prerequisites installed (see this guide for those instructions). Additionally, you're likely to want to have Leiningen installed, since many many projects use it for running builds, tests, and tasks.

To support specific features of this emacs configuration, there are three more prerequisites:

1. git is the dominant system for source code version control. There's a good chance it came installed with your operating system of choice, but in case it didn't, you'll want it!
2. clojure-lsp enables Find References, live linting, and many more features.
3. To get nice icons in your modeline, you need the fonts installed. After startup the first time, run M-x all-the-icons-install-fonts. You will only need to do this once.

A Word About Project-Wide Search

One of the capabilities that comes in very handy is searching for some text across all the files within your project. You can use git for that with the following command: M-x counsel-git-grep. This works just fine, with the caveat that it must be in a directory version-controlled with git. There are quite a few alternative search utilities, but you'll have to install them separately. In practice, you'll probably settle on one you like and use it exclusively. Here are the links, along with the emacs command to invoke each:

• ack M-x counsel-ack
• The Silver Searcher M-x counsel-ag
• The Platinum Searcher M-x counsel-pt
• ripgrep M-x counsel-rg

Features

This will allow you to edit Clojure files with syntax-aware highlighting and structural editing via paredit, which means it will keep all your delimiters for nested forms balanced (think parens, square brackets, and curly braces). Check out this animated guide to paredit. It's one of those things that seems strange at first, but once you get used to it, you won't want to edit Clojure without it!

Other excellent capabilities you'll want to know about include:

• CIDER, a fully interactive Clojure environent
• clojure-lsp, provides static analysis features for Clojure, such as live style and syntax warnings
• Projectile, navigate and manage project files
• Magit, a complete interface to git
• Treemacs, a tree layout file explorer

Upgrading

Each package we use gets updated by its authors, at whatever cadence works for them. It's a good idea to stay up-to-date, to get improvements and bug fixes. It's analogous to keeping the software up-to-date in your operating system.

When you run M-x list-packages it refreshes the cache of all the package repositories, and then tells you in the status line whether there are any updates to install. Press U to mark all upgradeable packages for installation, and then press x to execute the installation. You will be prompted to confirm, and when you press y the package updates will be installed. Press q to exit the package list when it's finished.

If you ever get curious to look, you can find all the installed packages in ~/.emacs.d/elpa.

Organization

I've tried to separate everything logically and document the purpose of every line. init.el acts as a kind of table of contents. It's a good idea to eventually go through init.el and the files under the customizations directory so that you know exactly what's going on.

Supporting CSS, HTML, JS, etc.

Emacs has decent support for CSS, HTML, JS, and many other file types out of the box, but if you want better support, then have a look at my personal emacs config's init.el. It's meant to read as a table of contents. The emacs.d as a whole adds the following:

• Customizes js-mode and html editing
  • Sets indentation level to 2 spaces for JS
  • enables subword-mode so that M-f and M-b break on capitalization changes
  • Uses tagedit to give you paredit-like functionality when editing html
  • adds support for coffee mode
• Uses enh-ruby-mode for ruby editing. enh-ruby-mode is a little nicer than the built-in ruby-mode, in my opinion.
  • Associates many filenames and extensions with enh-ruby-mode (.rb, .rake, Rakefile, etc)
  • Adds keybindings for running specs
• Adds support for YAML and SCSS using the yaml-mode and scss-mode packages

In general, if you want to add support for a language then you should be able to find good instructions for it through Google. Most of the time, you'll just need to install the "x-lang-mode" package for it.