witgen 0.2.0

# witgen

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witgen is a library to help you generate [wit definitions](https://github.com/bytecodealliance/wit-bindgen/blob/main/WIT.md) in a wit file for WebAssembly. Using this lib in addition to [wit-bindgen](https://github.com/bytecodealliance/wit-bindgen) will help you to import/export types and functions from/to wasm module.

## Getting started

- Put this dependency in your `Cargo.toml`

```toml
witgen = "0.2"
```

- Install `cargo witgen` CLI

```bash
$ cargo install cargo-witgen
```

## Examples

- Into your Rust code:

```rust
use witgen::witgen;

#[witgen]
struct TestStruct {
    inner: String,
}

#[witgen]
enum TestEnum {
    Unit,
    Number(u64),
    String(String),
}

#[witgen]
fn test(other: Vec<u8>, test_struct: TestStruct, other_enum: TestEnum) -> Result<(String, i64), String> {
    Ok((String::from("test"), 0i64))
}
```

- Then you can launch (at the root of your package):

```bash
$ cargo witgen generate
```

- It will generate a `witgen.wit` file at the root of your package:

```wit
record TestStruct {
    inner: string
}

variant TestEnum {
    Unit,
	Number(u64),
	String(string),
}

test : function(other: list <u8>, test_struct: TestStruct, other_enum: TestEnum) -> expected<tuple<string, s64>>
```

## Roadmap:

- Implement proc macro `#[witgen]` to put on enum, struct and functions
- Add proc_macro options (rename, file ?, ...)