@webassemblyjs/wast-parser

What is @webassemblyjs/wast-parser?

@webassemblyjs/wast-parser is a JavaScript library that provides tools for parsing WebAssembly Text Format (WAT or WAST) into an Abstract Syntax Tree (AST). This is useful for developers who need to analyze, transform, or generate WebAssembly code programmatically.

What are @webassemblyjs/wast-parser's main functionalities?

Parsing WAST to AST

This feature allows you to parse a WAST string into an AST. The code sample demonstrates how to parse a simple WebAssembly module written in WAST format into its corresponding AST representation.

const wastParser = require('@webassemblyjs/wast-parser');
const wast = `(module
  (func $add (param $lhs i32) (param $rhs i32) (result i32)
    get_local $lhs
    get_local $rhs
    i32.add)
)`;
const ast = wastParser.parse(wast);
console.log(JSON.stringify(ast, null, 2));

Error Handling

This feature provides error handling capabilities when parsing invalid WAST code. The code sample shows how to catch and handle parsing errors.

const wastParser = require('@webassemblyjs/wast-parser');
const invalidWast = `(module
  (func $add (param $lhs i32) (param $rhs i32) (result i32)
    get_local $lhs
    get_local $rhs
    i32.add
)`; // Missing closing parenthesis
try {
  const ast = wastParser.parse(invalidWast);
} catch (e) {
  console.error('Parsing error:', e.message);
}

AST Traversal

This feature allows you to traverse the AST generated from WAST. The code sample demonstrates a simple traversal function that logs the type of each node in the AST.

const wastParser = require('@webassemblyjs/wast-parser');
const wast = `(module
  (func $add (param $lhs i32) (param $rhs i32) (result i32)
    get_local $lhs
    get_local $rhs
    i32.add)
)`;
const ast = wastParser.parse(wast);
function traverse(node) {
  console.log(node.type);
  if (node.body) {
    node.body.forEach(traverse);
  }
}
traverse(ast);

Other packages similar to @webassemblyjs/wast-parser

wabt

WABT (WebAssembly Binary Toolkit) is a suite of tools for WebAssembly, including a WAST parser. It provides similar functionality to @webassemblyjs/wast-parser but also includes tools for converting between WAST and WASM, validating WebAssembly modules, and more.

assemblyscript

AssemblyScript is a TypeScript-like language that compiles to WebAssembly. It includes a parser for its own syntax, which is similar to WAST. While it is more focused on providing a high-level language for WebAssembly development, it offers some overlapping functionality with @webassemblyjs/wast-parser.

binaryen

Binaryen is a compiler and toolchain infrastructure library for WebAssembly. It includes a WAST parser and provides optimization and transformation tools for WebAssembly code. It is more comprehensive in terms of optimization and code generation compared to @webassemblyjs/wast-parser.

README

@webassemblyjs/wast-parser

WebAssembly text format parser

Installation

yarn add @webassemblyjs/wast-parser

Usage

import { parse } from "@webassemblyjs/wast-parser";

const ast = parse(source);