seoul256 in Jekyll code snippets

1. Introduction 🔗

seoul256 🔗 is a great colour scheme that seized my personal number 1 spot from Monokai the second I saw it. I ported it to Jekyll (i.e. Pygments 🔗 / Rouge 🔗 CSS) so that you can enjoy it, too. You can find the source code here 🔗 . Check it out below.

2. Examples 🔗

2.1. C example 🔗

Inline C like this int x = 4;

Code block like zis

#include "ruby/ruby.h"
static int
clone_method_i(st_data_t key, st_data_t value, st_data_t data)
    clone_method((VALUE)data, (ID)key, (const rb_method_entry_t *)value);
    return ST_CONTINUE;

2.2. Clojure example 🔗

(defn make-adder [x]
  (let [y x]
    (fn [z] (+ y z))))
(def add2 (make-adder 2))
(add2 4)

2.3. TypeScript example 🔗

export interface Animal {
  legs: number
  tails: number
type Cat<Pattern> = Animal & {
  swoosh?: (number) => void
  meow: (string) => string
  pattern: Pattern
// TODO: write Bird interface
// const utsuho: Bird = { ... }
const mike: Cat = {
  legs: 2,
  tails: 1,
  meow: (target) => `Hello! Wanna buy some cards, ${target ?? 'chump'}?`
  pattern: 'calico',
function yeet(target: any) => {
  throw target
let count = 1
while (true) {
  const target = 'nerd #' + count.toString()
  count = count + 1

2.4. Zig example 🔗

const std = @import("std");
const warn = std.debug.warn;
fn add_floats(x: f16, y: f16) f16 {
    return x + y;

3. Porting process 🔗

One article 🔗 I found suggested an external script that would attempt to parse VimL through Python and it wasn't working out for me in part due to the complexity of the seoul256.vim implementation, and in part due to the script not seeming to work on modern Python (it was eight years old :scream:).

I cut out some middle-steps at the cost of some added manual labour to get the job done instead. Since vim is a scriptable editor, I figured it would be no problem exporting the colours if I could just figure out how, and I was right.

To outline the process:

  1. Run :runtime syntax/hitest.vim inside vim. This will run a thorough colour test in vim.
  2. Run :TOhtml in vim. This will convert the current buffer to a HTML page, complete with your colour scheme in use.
  3. Strip the generated HTML to just the contents of the <style> tag in the <head>.
  4. Remove style-rules related only to plugins to clean things up. I found I had hundreds if not thousands of selectors for CHADtree 🔗 and nvim-colorizer.lua 🔗 .1
  5. Copy an existing stylesheet, e.g minima classic 🔗
  6. Replace the values of the stylesheet you copied with the values you got from your colour test stylesheet. There aren't always 1:1 relations here, but you can make a best effort for sure.

This method certainly has room for improvement. If I were to automate it, I'd make it a lua script for neovim. Most of all I wish there were a proper standard for colour schemes though, and I have no real incentive to work further on this.

4. Footnotes 🔗

  1. This is not a dig at either plugin; I use them because they are both great at what they do. Their internal workings are beyond my expertise and I do not judge their code by this metric.