https://github.com/oltdaniel/zig-wasm-example
exploring wasm with zig
https://github.com/oltdaniel/zig-wasm-example
wasm zig
Last synced: about 2 months ago
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exploring wasm with zig
- Host: GitHub
- URL: https://github.com/oltdaniel/zig-wasm-example
- Owner: oltdaniel
- License: mit
- Created: 2024-06-29T11:56:03.000Z (almost 2 years ago)
- Default Branch: main
- Last Pushed: 2024-07-16T16:49:34.000Z (almost 2 years ago)
- Last Synced: 2025-03-30T14:17:56.904Z (about 1 year ago)
- Topics: wasm, zig
- Language: Zig
- Homepage:
- Size: 58.6 KB
- Stars: 5
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Zig WASM Example
> [!IMPORTANT]
> This project has been re-written as an actual library and can be found at [oltdaniel/zig-js-interplay](https://github.com/oltdaniel/zig-js-interplay). This repo will probably be archived in the future.
This repo is playing with Zig and WASM to see how easy or hard it is passing values between them, without an ready-to-go generator like in `wasm-pack` for Rust.
## Example
This is an example which hides type handling behind a Helper class.
> See full example in [`www/index.html`](./www/index.html) and [`src/wasm.zig`](./src/wasm.zig).
```js
import ZigWASMWrapper from './helper.js';
let wasm = await ZigWASMWrapper.initialize("./main.wasm");
console.log(wasm.greet("Daniel"));
// => prints "Hello Daniel!"
wasm.printJSON({message: "Greetings"});
// => prints "JSON = {"message":"Greetings"}!"
wasm.silence();
// => does nothing
wasm.testFunction((...args) => {
console.log('I got called from zig with these arguments=', args)
})
// => prints "I got called from zig with these arguments= ['Hello', 'World]"
```
And the zig code excluding the type hanlding is also straightforward:
```zig
// type definitions and imports
export fn greet(arg: String) String {
// Get the real value passed to us by javascript
const name = arg.value();
// ... this ignores some code of the actual code to print a message in between
// Generate a new greet message that we can return
const greetMessage = std.fmt.allocPrint(gpa, "Hello {s}!", .{name}) catch @panic("Oops");
// Return the greet message as a compatible type
return String.init(greetMessage);
}
export fn printJSON(arg: JSON) void {
const message = std.fmt.allocPrint(gpa, "JSON = {s}!", .{arg.value()}) catch @panic("Oops");
js.log(String.init(message));
}
export fn testFunction(arg: Function) AnyType {
const args = Array.from(&.{ String.init("Hello").asAny(), String.init("World").asAny() });
return arg.call(args);
}
```
## Documentation
> **TODO**: Write documentation on the encoding and examples for each type and scenario.
## Requirements
- zig, I'm running the latest release `0.13`
- python, to serve the output
- make, just as a command shortcut tool
## Running
```bash
# compile the wasm file
make
# start the server
make server
```
## Information
A small blog article on how I ended up writing this repo: [Playing with zig and wasm](https://oltdaniel.eu/blog/2024/playing-with-zig-and-wasm.html)
## Known pitfalls
- Introducing the dynamic and untyped nature of JS into Zig requires additional verification of types during runtime. Other libraries generate the JS interface to avoid pitfalls like this, but they require an additional compile step and delivery of the custom compiled WASM file as well as the JS file. Thereby, assuming types is ignorant just like in JS and you need to verify them "manually". **NOTE**: The Compatible Types built in Zig verify their type when a type specific action is executed (like calling `.value()` or `.call()`).
- When Zig returns or accepts non-compatible types, the behavior is undefined or rather the same was with not using the library. This means, the built-in abstraction on the JS side won't work as it expects compatible types.
- There is currently no abstraction for memory allocation. If something like a string of length zero is requested for allocation, it fails.
## ToDo
- [ ] Memory abstraction for error handling
- [ ] Clean-up of code
- [ ] Documentation
## License
[LICENSE MIT](./LICENSE)