Create Your Own Programming Language with Rust

Learn compiler fundamentals by building four languages from scratch

Overview • Languages • Quick Start • Requirements • Book

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Edition 1.0 Complete
Four languages covering interpretation, compilation, type systems, and object-oriented programming.
LLVM code generation, JIT compilation, type inference, and memory management.

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Overview

This book arose from frustration with the lack of modern, clear, and concise teaching materials for beginners who want to learn how to create their own programming language.

"If you don't know how compilers work, then you don't know how computers work" ¹

"If you can't explain something in simple terms, you don't understand it" ²

Languages

The book teaches programming language implementation through four progressively complex languages:

Language	Type System	Execution	Features	Rust Version
Calculator	None	Interpreter/VM/JIT	Arithmetic expressions	stable / nightly
Firstlang	Dynamic	Interpreter	Variables, functions, recursion	stable 1.70+
Secondlang	Static	LLVM JIT	Type inference, compilation	nightly + LLVM
Thirdlang	Static	LLVM JIT	Classes, methods, OOP	nightly + LLVM

create-your-own-lang-with-rust/
├── calculator/     # Simple arithmetic (interpreter, VM, JIT backends)
├── firstlang/      # Interpreted language with recursion
├── secondlang/     # Compiled language with type inference
├── thirdlang/      # Object-oriented with classes and methods
└── book/           # mdbook source for createlang.rs

Each language has its own README with detailed instructions.

Quick Start

Firstlang (stable Rust)

cd firstlang
cargo run -- examples/fibonacci.fl    # Run a program
cargo run                              # Start REPL

Secondlang (nightly + LLVM)

cd secondlang
rustup run nightly cargo run -- examples/fibonacci.sl
rustup run nightly cargo run -- --ir examples/fibonacci.sl   # View LLVM IR

Thirdlang (nightly + LLVM)

cd thirdlang
rustup run nightly cargo run --bin thirdlang -- examples/point.tl
rustup run nightly cargo run --bin thirdlang -- examples/counter.tl

Calculator

cd calculator
cargo run --bin main examples/simple.calc                              # Interpreter
cargo run --bin main --features vm examples/simple.calc                # VM
rustup run nightly cargo run --bin main --features jit examples/simple.calc  # JIT

Requirements

Stable Rust (Calculator interpreter/VM, Firstlang)

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

Nightly Rust + LLVM (Calculator JIT, Secondlang, Thirdlang)

# Install nightly
rustup toolchain install nightly

# Install LLVM
# macOS:
brew install llvm

# Debian/Ubuntu:
# See https://apt.llvm.org/

Check your LLVM version and update Cargo.toml accordingly:

LLVM Version	inkwell feature
20.x	llvm20-1
19.x	llvm19-1
18.x	llvm18-1

Running Tests

# All projects
cargo test -p calculator -p firstlang
rustup run nightly cargo test -p secondlang -p thirdlang

Building the Book

cd book
mdbook serve    # Local preview at http://localhost:3000
mdbook build    # Build static site

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