Field

Programming & Computer Science

Build the systems you use every day, starting with an interpreter, until nothing about them is magic.

Start building

Build an Interpreter

Write an `evaluate` function and grow it from arithmetic to a small language with variables, functions, conditionals, and data structures. By the end, you understand these constructs more deeply, because you built them yourself.

11 problems
interpreter recursion evaluation functions

Build Hangman

Build a word-guessing game by breaking it into small, testable pieces. Learn to decompose a problem into functions and write tests that check your own work.

5 problems
tdd testing game-logic functions

Coming next

  • Build a Compiler

    Write a `compile` function that turns the same language you interpreted into stack bytecode, then build the virtual machine that runs it. By the end, you see both halves of what "compile" means -- and the hidden dependency your VM leans on.

  • Build a JavaScript Runtime

    Build JavaScript's call stack, event loop, and task queues from scratch. You run real JS through your own runtime and see exactly why console.log, setTimeout, and Promise.then execute in the order they do.