WASI gives Emacs awesome power !!
This provides the ability to run WASI: WebAssembly System Interface
program on Emacs.
This is still in the experimental stage.
This module is developed using wasmtime
.
Build
$ cargo build
Usage
Set up the following in your emacs.
;; load wasm loader
(module-load "path/to/target/debug/libwasm_loader.so")
;; register wasm modules
(wasm-loader/load "path/to/wasm-dir/")
Use wasm-loader/call
to run program on WASI.
;; call hello.wasm
(message (wasm-loader/call "hello" "test" "{ \"name\": \"WASM\" }"))
Emacs interface for WASI
Basically, stdio is used to communicate with program.
To run on WASI, use the function wasm-loader/call
.
This function takes three arguments.
- wasm module name (this is the file name with the extension removed)
- command type argument (e.g., get, setting )
- command argument body (This is passed to the stdio. e.g., JSON for RPC requests)
WASI program reads the 2 and 3.
Here is a simple example of a program.
see examples/hello/main.rs
.
use serde::{Deserialize, Serialize};
use std::io::{self, Read};
#[derive(Serialize, Deserialize, Debug)]
struct Request {
name: String,
}
#[derive(Serialize, Deserialize, Debug)]
struct Response {
command: String,
name: String,
}
// This is a sample program that uses stdio to exchange values using the JSON format.
fn main() {
// Reads args from Emacs from stdin.
let mut raw_stdin: Vec<u8> = Vec::new();
let mut stdin = io::stdin();
stdin.read_to_end(&mut raw_stdin).ok();
// convert
let input: String = String::from_utf8(raw_stdin).unwrap();
// deserialize
let req: Request = serde_json::from_str(&input).unwrap();
// create return response
let mut res = Response {
command: "".to_string(),
name: format!("hello {}", req.name),
};
let args: Vec<String> = std::env::args().collect();
if !args.is_empty() {
// get command type from args
let arg = args[0].clone();
res.command = arg;
}
// to json
let serialized = serde_json::to_string(&res).unwrap();
println!("{}", serialized);
}
build WASI program.
$ cd example/hello
$ cargo build --target wasm32-wasi