2635ccb742
* Rename the `wasmtime_api` library to match the containing `wasmtime` crate
Commit d9ca508f80 renamed the
`wasmtime-api` crate to `wasmtime`, but left the name of the library it
contains as `wasmtime_api`.
It's fairly unusual for a crate to contain a library with a different
name, and it results in rather confusing error messages for a user; if
you list `wasmtime = "0.7"` in `Cargo.toml`, you can't `use
wasmtime::*`, you have to `use wasmtime_api::*;`.
Rename the `wasmtime_api` library to `wasmtime`.
* Stop renaming wasmtime to api on imports
Various users renamed the crate formerly known as wasmtime_api to api,
and then used api:: prefixes everywhere; change those all to wasmtime::
and drop the renaming.
wasmtime-rust - Using WebAssembly from Rust
This crate is intended to be an example of how to load WebAssembly files from a
native Rust application. You can always use wasmtime and its family of crates
directly, but the purpose of this crate is to provide an ergonomic macro:
#[wasmtime_rust::wasmtime]
trait WasmMarkdown {
fn render(&mut self, input: &str) -> String;
}
fn main() -> anyhow::Result<()> {
let mut markdown = WasmMarkdown::load_file("markdown.wasm")?;
println!("{}", markdown.render("# Hello, Rust!"));
Ok(())
}
The wasmtime macro defined in the wasmtime-rust crate is placed on a trait
which includes the set of functionality which a wasm module should export. In
this case we're expecting one render function which takes and returns a
string.
The macro expands to a struct with all of the methods on the trait (they must
all be &mut self) and one function called load_file to actually instantiate
the module.
Note that this macro is still in early stages of development, so error messages aren't great yet and all functionality isn't supported yet.
Missing features
Currently if the wasm module imports any symbols outside of the WASI namespace the module will not load. It's intended that support for this will be added soon though!