My Emacs Clojure Development Environment Overview

2020 November 12

Preface

To me, Emacs isn't a text editor but rather an extremely flexible development environment that allows anyone to optimize their workflow. I used to be a Vim user and did everything inside the terminal: Vim for code editing, bash commands for running/testing code, and git cli for all other git operations. I wasn't in any sense a Vim superuser. However, I felt pretty comfortable to do most of my day-to-day work inside the terminal.

For the past two years, I got into the Clojure programming community and made a very audacious move to learn Emacs at the same time. To me, learning Emacs was just as hard, if not harder, as learning Clojure itself. However, learning either subjects has paid off far more than I had expected. In this post, I will share an overview of my current development environment setup and explain my rationale of some of the key bindings that I use.

Magit - git porcelain

Magit is one of the most powerful powerful packages available on Emacs. It is also the package that made me rethink my entire workflow. If you don't known, Magit is a git porcelain that makes all the fancy git operations within Emacs. I used to enjoy doing all git operations inside terminal. I rarely do it lately because of how great Magit is. If I were to stop using Emacs for writing code, I'd definitely continue using Magit until I find another comparable tool.

I bind magit-status to command+g (also <SPC> g g because of old habit using Doom Emacs.)

Cider - advanced Clojure integrated environment

I use Cider to manage the nrepl sessions and to evaluate code. I used to rely on Cider for more things like looking up code definition but lately I've been experimenting that with clojure-lsp which I'll describe in the next section.

I bind the Cider keys under a local leader key <,>, which is only available in the clojure(script)-mode. This is a habit I developed during the time using Spacemacs and Doom Emacs though their keymaps are slightly different. Currently I only use it to evaluate code in three levels - to evaluate buffer, evaluate top-level vars, and evaluate s-expression. They are currently bound to <,> e b, <,> e f, and <,> e e, which I'll probably simplify by removing the middle e later.

LSP - code jumping

LSP is the text editor-agnostic protocol for IDE-like operations. It separates the concerns of those IDE-like capabilities and the actual implementation. For example, the LSP defines the capability of textDocument/definition and the clojure-lsp implements how to find the definition of a particular Clojure symbol. In Emacs, AFAIK there are two packages to support LSP interactions, lsp-mode and eglot. I've tried both in the past but I'm sticking with lsp-mode at the moment.

I bind command+l to the lsp-keymap-prefix while I'm still learning it. So far I only need two functions: lsp-find-definition and lsp-find-references which are bound to command+l g g and command+l g r respectively. I'll definitely re-bind those keys for easier access.

Lispy + Lispyville - general lisp s-expression editing

I use Lispy and Lispyville for most of the e-expression editing in Clojure mode instead of using smartparens or paredit or parinfer. I like the safe evil operations that are remapped by Lispyville so I don't need to worry about unbalanced parens. However, I don't use a lot of the keys other than slurping, barfing, and dragging s-expressions.

Dired - file management

I bind dired to <SPC> d with just two key strokes for easier access. Dired mode was a powerful package that I overlooked for so long. It finally came into my radar thanks to the amazing video by David Wilson. Dired was truly a missing piece in my workflow centered around Emacs. Having the ability to browse the filesystem naturally inside the Emacs buffer was absolutely a joy.

Eshell - direct shell access

This is bound to <SPC> e also for easier access. With all the packages above, there are rarely things I need to do directly in shell. For those things that has to be done inside shell, I usually do it in Eshell. However, there are times I do need something closer to the native terminal app on OSX, something I can start a long running process and bury it in the background. In these cases I'll launch vterm instead. However, for some those off tasks like compiling code or start a docker container in the background, I prefer Eshell.

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