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Writing Clojure With Vim In 2013

January 16, 2013 — 3 minutes long

It’s now 2013. Vim is still my favorite text editor, and Clojure has become my favorite programming language.

A couple of recent plugins have made writing Clojure in Vim an absolute joy.

vim-clojure-static

vim-clojure-static by Sung Pae is an extraction of the excellent VimClojure plugin. But it does a few things better. Overall, it’s simpler. It leaves out functionality better served by existing Vim plugins like rainbow_parentheses.vim. It’s lightweight and the source is more accessible since it doesn’t have to include a REPL interface. What it does provide is VimClojure’s excellent syntax, indent, and filetype settings, along with some nice user settings, like fuzzy indenting and pretty multiline strings.

This sets up a great base for editing Clojure.

vim-foreplay

But alas, if one only installed vim-clojure-static, he or she would be missing out on so much. Here is where we get to the meat of Clojure development in Vim: Tim Pope’s excellent vim-foreplay. This is where we find our REPL interface, though, as Tim says, it’s “not quite a REPL”. And that’s actually perfect.

If you’ve ever tried to use a REPL interface in Vim, you’ll know it’s a dog. The Vim buffer is not meant to be a command line. vim-foreplay leverages Vim’s great buffer editing abilities instead of fighting against them. The result is something magical.

For example, say I have some Clojure code in a buffer:

(deftest test-two
  (is (= 2 2)))

I can put my cursor over any part of that is form, then press cpp, and instantly see true at the bottom of the editor. So I know this test will pass, and I just wrote it! I could even do the same with that deftest form, and now the test-two function is instantly available for run-tests.

I could also put my cursor on that is form again, press K, and immediately see its documentation. But if the documentation is not good enough and I need to see the source — quite common in practice — I can press [<ctrl-d> and be in a buffer with the unzipped and running Clojure source.

Need a quick little prompt for a one-off command? cqp! Or perhaps a Vim scratchpad where hitting enter evaluates the current line? cqc! And then there’s cqq, which is just like cqc, but it will copy the form underneath the cursor into the scratchpad.

There’s even more excitment to vim-foreplay, but I’ll leave that to the reader to discover. The six aforementioned commands have spoiled me for programming with any other language. Coding in Clojure with vim-foreplay is just too much fun, probably because feedback is so immediate. It has changed the way I program and learn.