WebAssembly Integration

PatchLang compiles to WebAssembly via wasm-pack, producing packages for both browser bundlers (Vite, webpack) and Node.js.

Building

./scripts/build-wasm.sh

Produces:

• pkg-web/ — browser bundler target (ES module + .wasm binary)
• pkg-node/ — Node.js target (CommonJS, synchronous loading)

Browser Usage (Vite)

// vite.config.ts
import wasm from 'vite-plugin-wasm'

export default defineConfig({
  plugins: [wasm()],
  resolve: {
    alias: {
      'patchlang-wasm': '/path/to/SignalCanvasLang/pkg-web/patchlang_wasm.js',
    },
  },
})

// src/parser.ts
import { parse, validate } from 'patchlang-wasm'

const result = JSON.parse(parse(source))
// result.program  — PatchProgram AST (matches TypeScript types)
// result.errors   — parse errors with byte-offset spans

Node.js Usage

const { parse, validate } = require('./pkg-node/patchlang_wasm.js')

const result = JSON.parse(parse(source))
console.log(result.program.statements.length)

API

parse(source: string): string

Parses PatchLang source and returns a JSON string:

{
  "program": {
    "type": "Program",
    "statements": [...]
  },
  "errors": []
}

The program field matches the TypeScript PatchProgram type used by the SignalCanvas frontend. All field names are camelCase, properties are Record<string, string> objects, and port directions are lowercase strings.

If there are parse errors, the parser recovers and produces a partial AST alongside the error list. Each error includes byte-offset spans for precise source location.

validate(source: string): boolean

Returns true if the source parses without errors. Faster than parse() when you only need a yes/no answer.

Error Format

{
  "message": "expected ']' to close port range",
  "span": { "start": 47, "end": 48 },
  "hint": "port ranges must be closed with ']'"
}

Use the span offsets to compute line/column numbers or highlight ranges in an editor.