1 unstable release

new 0.0.8	Apr 15, 2025

#465 in WebAssembly

MIT license

18KB
354 lines

`wat-fmt`

A pretty formatter for WebAssembly Text Format. It is fast, flexible, and supports Inference non-deterministic instructions.

Build

wat-fmt is a one file crate with #[no_std] support. It can be built for different targets. The standard cargo build command will build the crate for the host target.

Build for WASM

Since wat-fmt is a no_std crate, it can be built for WASM. This is useful for running the formatter in the browser or in a WebAssembly runtime.

Prerequisites:

cargo install wasm-pack

Alternatively, you can use another tool to build WASM binaries.

Uncomment the crate type in the Cargo.toml file:

[lib]
crate-type = ["cdylib"]

To build the crate for WASM, run the following command with the wasm feature:

wasm-pack build --target web --features wasm

Examples

Source: (module (func $add (param $a i32) (param $b i32) (result i32) (local $c i32) i32.uzumaki local.set $c local.get $a local.get $c i32.add) (export "add" (func $add) ) )

Formatted:

(module
  (func $add (param $a i32) (param $b i32) (result i32)
    (local $c i32)
    i32.uzumaki
    local.set $c
    local.get $a
    local.get $c
    i32.add
  )
  (export "add" (func $add) )
)

WebAssembly example

index.html:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>WAT Formatter</title>
    <script type="module">
        import {handleButtonClick} from './main.js';
    </script>
</head>
<body>
    <h1>WAT Formatter by <a href="https://inferara.com/">Inferara</a></h1>
    <textarea id="input" rows="10" cols="30">(module (func $add (param $a i32) (param $b i32) (result i32) (local $c i32) i32.uzumaki local.set $c local.get $a local.get $c i32.add) (export "add" (func $add) ) )</textarea>
    <button onclick="handleButtonClick()">Format Input</button>
    <h2>Output:</h2>
    <pre id="output"></pre>
    <script type="module" src="./main.js"></script>
</body>
</html>

main.js

import init, { format } from '../pkg/wat_fmt.js';

let wasmInitialized = false;

export async function initWasm() {
    await init();
    wasmInitialized = true;
}

export async function handleButtonClick() {
    if (!wasmInitialized) {
        console.error("WebAssembly module is not initialized.");
        return;
    }

    const input = document.getElementById('input').value;

    try {
        const result = format(input);
        document.getElementById('output').textContent = result;
    } catch (error) {
        console.error("Error calling format function:", error);
    }
}

window.onload = initWasm;
window.handleButtonClick = handleButtonClick;

License

MIT

Dependencies

~0–405KB