Alex Crichton 02b7021053 Leverage new rustc wasm features
This commit leverages two new attributes in the Rust compiler,
`#[wasm_custom_section]` and `#[wasm_import_module]`. These two attributes allow
removing a lot of hacks found in wasm-bindgen and also allows removing the
requirement of `wasm-opt` to remove the unused data sections.

This does require two new nightly features but we already required the
`proc_macro` nightly feature and these will hopefully be stabilized before that
feature!
2018-03-24 10:36:19 -07:00

40 lines
1.3 KiB
Rust

#![feature(proc_macro, wasm_custom_section, wasm_import_module)]
extern crate wasm_bindgen;
use wasm_bindgen::prelude::*;
// Definitions of the functionality available in JS, which wasm-bindgen will
// generate shims for today (and eventually these should be near-0 cost!)
//
// These definitions need to be hand-written today but the current vision is
// that we'll use WebIDL to generate this `extern` block into a crate which you
// can link and import. There's a tracking issue for this at
// https://github.com/alexcrichton/wasm-bindgen/issues/42
//
// In the meantime these are written out by hand and correspond to the names and
// signatures documented on MDN, for example
#[wasm_bindgen]
extern {
type HTMLDocument;
static document: HTMLDocument;
#[wasm_bindgen(method)]
fn createElement(this: &HTMLDocument, tagName: &str) -> Element;
#[wasm_bindgen(method, getter)]
fn body(this: &HTMLDocument) -> Element;
type Element;
#[wasm_bindgen(method, setter = innerHTML)]
fn set_inner_html(this: &Element, html: &str);
#[wasm_bindgen(method, js_name = appendChild)]
fn append_child(this: &Element, other: Element);
}
// Called by our JS entry point to run the example
#[wasm_bindgen]
pub fn run() {
let val = document.createElement("p");
val.set_inner_html("Hello from Rust!");
document.body().append_child(val);
}