Get Started with Purus

日本語

An interactive tutorial for the Purus programming language. Write real Purus code and let Vitest check your answers as you go.

Requirements

• Node.js >= 22

Setup

npm install
npm start

npm start asks for your language (English / 日本語) and copies the lessons into exercises/ — your working directory. All comments and READMEs in the copy are in the language you picked.

npm start -- en   # skip the prompt
npm start -- ja

Guided mode (recommended)

npm run guide

The guide finds your first incomplete lesson, runs its tests, and watches the folder — save main.purus to re-check, and it advances automatically when the tests turn green. (Ctrl+C to quit; progress is never lost.)

Manual mode

1. Open a lesson folder under exercises/ and read its README.md.

2. Edit main.purus in that folder to complete the TODOs.

3. Run the lesson's tests:

   npm test 01             # run lesson 01 only
   npm test                # run all lessons
   npm run test:watch 01   # re-run lesson 01 automatically on save

4. When the tests turn green, move on to the next lesson!

Check how far you've come at any time:

npm run progress

  ✅ 01-hello-world
  ⬜ 02-variables (0/2)
  ...
  1/17 lessons complete

Stuck? Each template folder in lessons/ has a solution.purus you can peek at.

To start over, run npm start again (it asks before overwriting your edits).

Lessons

#	Lesson	Topics
01	Hello, World	console.log, //;strings;//
02	Variables	const, let, be, add be
03	Strings	interpolation [expr]
04	Operators	add sub mul mod pow
05	Functions	fn, to return, calls with []
06	Conditionals	if / elif / else, eq gt
07	Loops	while, for ... in
08	Arrays	literals, [\0], ranges, destructuring
09	Objects	literals, object[...] destructuring
10	Switch	switch / case / blank
11	Pipeline & Nullish	pipe, coal
12	Classes	class, fn new, this
13	Error Handling	throw, try / catch
14	Async	async fn, await
15	Standard Library	use p-math, use p-array
16	Generators	yield
17	FizzBuzz (Capstone)	everything combined 🎓

For developers / forks

lessons/ holds the templates: per-language starters (main.en.purus, main.ja.purus), READMEs (README.md, README-ja.md), a solution.purus, and the lesson's tests. npm start copies them into exercises/ (gitignored), so learners never modify the templates.

Script	Description
npm run test:solutions	Verify every solution.purus passes its lesson tests
npm run format	Format with Prettier
npm run lint	Lint with purus-lint

Learn more

• Purus Documentation
• Playground