add wasi

wasi/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "wasi"
+version = "0.1.0"
+authors = ["Hatter Jiang <jht5945@gmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

wasi/README.md

@@ -0,0 +1,39 @@
+
+```shell
+rustup target add wasm32-wasi
+```
+
+```shell
+cargo build --target=wasm32-wasi
+```
+
+```shell
+$ ls target/
+debug  wasm32-wasi
+```
+
+
+运行时（Runtime）
+运行这个文件，需要一个运行时（Runtime）。你也可以把这个理解成一个“容器”，“虚拟机”什么的，都行。但是准确的叫法是：运行时。
+
+目前常见的运行时有 wasmtime，wasmer 等。
+
+我们这次用 wasmtime 来运行吧。
+
+`curl https://wasmtime.dev/install.sh -sSf | bash`
+
+or download from:
+
+https://github.com/bytecodealliance/wasmtime/releases
+
+
+```
+$ wasmtime --dir=. target/wasm32-wasi/debug/wasi.wasm
+Hello, world!
+```
+
+
+
+https://mp.weixin.qq.com/s/VYkUvD1NpRdx_qoIdCCq8w - _【Rust每周一知】Rust, wasm, wasi 试玩儿_
+
+

wasi/src/main.rs

@@ -0,0 +1,10 @@
+use std::fs::File;
+use std::io::prelude::*;
+
+fn main() -> std::io::Result<()> {
+    let mut file = File::create("foo.txt")?;
+    file.write_all(b"Hello, world!")?;
+    println!("Hello, world!");
+    Ok(())
+}
+