Introduction

Wax is a Rust-like syntax for WebAssembly that compiles to standard Wasm binary or text formats. It provides a more familiar programming experience while maintaining a direct correspondence to WebAssembly concepts.

Why Wax?

WebAssembly Text format (WAT) uses S-expressions and stack-based operations, which can be verbose and unfamiliar to most programmers:

(func $add (param $x i32) (param $y i32) (result i32)
  local.get $x
  local.get $y
  i32.add)

Wax provides an expression-oriented syntax that feels more natural:

fn add(x: i32, y: i32) -> i32 {
    x + y
}

Both compile to identical WebAssembly bytecode.

Installation

Requirements: Opam (2.1+) and OCaml 5.0+.

# Install dependencies
opam install . --deps-only

# Build
dune build

# Install globally
opam install .

Quick Start

Create a file hello.wax:

#[export = "add"]
fn add(x: i32, y: i32) -> i32 {
    x + y
}

#[export = "factorial"]
fn factorial(n: i32) -> i32 {
    if n <= 1 {
        1
    } else {
        n * factorial(n - 1)
    }
}

Compile to WebAssembly binary:

wax hello.wax -o hello.wasm

Or convert to WebAssembly text format to see the generated WAT:

wax hello.wax -f wat

Supported Conversions

Wax supports all 9 combinations of input and output formats:

Input	Output	Use Case
`.wax`	`.wasm`	Compile to binary
`.wax`	`.wat`	Compile to text
`.wax`	`.wax`	Format / type-check
`.wat`	`.wasm`	Assemble to binary
`.wat`	`.wax`	Decompile to Wax
`.wat`	`.wat`	Format
`.wasm`	`.wat`	Disassemble
`.wasm`	`.wax`	Decompile to Wax
`.wasm`	`.wasm`	Round-trip

Type Checking

Enable type checking with the -v flag:

wax hello.wax -v -o hello.wasm

This catches type errors before generating output:

error: type mismatch
  --> hello.wax:3:5
   |
 3 |     x + y
   |     ^^^^^ expected f32, found i32

Next Steps

Language Guide — Variables, expressions, and control flow
Correspondence — How Wax maps to WebAssembly
CLI Reference — Complete command-line options

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