Install

Fern is a Go-built compiler. Until prebuilt binaries land, build from source — one command.

Prerequisites

• Go 1.24+ (download). The compiler is a single Go module with no external dependencies.
• A C linker for native targets (clang or gcc; cc is fine). Only needed to produce ELF / Mach-O executables; the WASM target needs no linker.

Build the toolchain

git clone https://github.com/JakeChampion/lang
cd lang
go build -o ~/.local/bin/fern ./cmd/fern

fern is now on your PATH. Verify:

fern -help

Companion binaries

Binary	Build command	Purpose
fern	go build ./cmd/fern	The main compiler + runner.
fern-lsp	go build ./cmd/fern-lsp	Language server for editors.
dump_arm64	go build ./cmd/dump_arm64	Disassemble an emitted .s file.
dump_wat	go build ./cmd/dump_wat	Inspect a .wat module.

Run hello, world

Save this as hello.fern:

function main(): i32 {
    print("hello, world");
    return 0;
}

Run it under the interpreter:

fern -interp hello.fern

Or compile to wasm and run under wasmtime:

fern -target wasm -o hello.wasm hello.fern
wasmtime hello.wasm

Next: First steps →