09ccdc9285
* Add documentation for building programs using AssemblyScript. * Add the assemblyscript hello world as an example and display it inline. * Move the AssemblyScript hello world into the docs directory. That way Cargo doesn't try to run it like a Rust example.
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AssemblyScript
AssemblyScript 0.10.0 includes support for targeting WASI. To use it, add
import "wasi" at the top of your entrypoint file.
To create a program which can be run directly as a command, pass --runtime half
to the AssemblyScript linker. This selects the half runtime, which ensures that
the generated wasm module doesn't contain any extraneous exports. (This isn't
strictly required today, but the handling of extraneous exports may change in
the future, so it's encouraged. As a bonus, it also reduces code size.)
To create a program which can be loaded as a library and used from other modules, no special options are needed.
Let's walk through a simple hello world example.
wasi-hello-world.ts
{{#include ./assemblyscript-hello-world/wasi-hello-world.ts}}
This uses as-wasi as a dependency to make working with the AssemblyScript WASI bindings easier. Then, you can run:
asc wasi-hello-world.ts -b wasi-hello-world.wasm
to compile it to wasm, and
wasmtime wasi-hello-world.wasm
to run it from the command-line. Or you can instantiate it using the Wasmtime API.
package.json
It can also be packaged using a package.json file:
{{#include ./assemblyscript-hello-world/package.json}}
You can also browse this source code online and clone the wasmtime repository to run the example locally.