@webassemblyjs/wast-parser

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);