This commit starts wasm-bindgen down the path of supporting closures. We
discussed this at the recent Rust All-Hands but I ended up needing to pretty
significantly scale back the ambitions of what closures are supported. This
commit is just the initial support and provides only a small amount of support
but will hopefully provide a good basis for future implementations.
Specifically this commit adds support for passing `&Fn(...)` to an *imported
function*, but nothing elese. The `&Fn` type can have any lifetime and the JS
object is invalidated as soon as the import returns. The arguments and return
value of `Fn` must currently implement the `WasmAbi` trait, aka they can't
require any conversions like strings/types/etc.
I'd like to soon expand this to `&mut FnMut` as well as `'static` closures that
can be passed around for a long time in JS, but for now I'm putting that off
until later. I'm not currently sure how to implement richer argument types, but
hopefully that can be figured out at some point!
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!
This'll allow binding multiple signatures of a JS function as well as otherwise
changing the name of the JS function you're calling from the Rust function that
you're defining.
Closes#72
This attribute indicates that methods are to be accessed in a structural method
rather than through their class. This should allow direct access to properties
embedded on objects rather than forcing all objects to have a class/prototype.
Along the way remove the namespace in Rust as this ended up causing too many
problems, alas! The `js_namespace` attribute now almost exclusively modifies the
JS bindings, hence the "js" in the name now.
This commit renames the `static` attribute to `namespace` and simultaneously
reduces and expands the scope. The `namespace` attribute can now be applied to
all imports in addition to functions, and it no longer recognizes full typed
paths but rather just a bare identifier. The `namespace` attribute will generate
a Rust namespace to invoke the item through if one doesn't already exist (aka
bindign a type).
Building on the previous commit to invoke not invoke `npm install` this takes
the commit a step further (to hopefully fix some races) to use Webpack's native
bundled wasm support.
It turns out the circular dependencies between the wasm module and the module
using it wasn't quite working out so a number of imports had to be tweaked, but
otherwise it's a nice transition where we don't have to base64 encode anything
in tests any more!
These tend to have one "pretty obvious" definition in JS anyway, so
let's paper over this deficiency in rustc for now by automatically
resolving any imports for these functions.
Closes#28
This'll match more closely what wasm eventually does natively, which is
importing these functions directly and not allowing changing them over time.
Closes#25
This commit migrates from `wasm_bindgen!`-the-macro to
`#[wasm_bindgen]`-the-attribute. The actual mechanics of the macro are
relatively simple in just generating some shims here and there, but wrapping
everything in one huge macro invocation can often seem intimidating as it gives
off this feeling of "oh dear anything can happen here!" Using an attribute
should curb expectations much more greatly of "oh there's just some extra stuff
happening behind the scenes".
The usage is otherwise relatively straightforward and close to what it was
before, but check out the DESIGN.md/README.md changes for more info!
Push the compiler to do trait resolution to figure out what each type is bound
with in JS, and that way we can accept effectively all types (so long as they
implement a trait).
This commit is a mostly-rewrite of the `wasm-bindgen` tool. After some recent
discussions it's clear that the previous model wasn't quite going to cut it, and
this iteration is one which primarily embraces ES6 modules and the idea that
this is a polyfill for host bindings.
The overall interface and functionality hasn't changed much but the underlying
technology has now changed significantly. Previously `wasm-bindgen` would emit a
JS file that acted as an ES6 module but had a bit of a wonky interface. It
exposed an async function for instantiation of the wasm module, but that's the
bundler's job, not ours!
Instead this iteration views each input and output as a discrete ES6 module. The
input wasm file is interpreted as "this *should* be an ES6 module with rich
types" and the output is "well here's some ES6 modules that fulfill that
contract". Notably the tool now replaces the original wasm ES6 module with a JS
ES6 module that has the "rich interface". Additionally a second ES6 module is
emitted (the actual wasm file) which imports and exports to the original ES6
module.
This strategy is hoped to be much more amenable to bundlers and controlling how
the wasm itself is instantiated. The emitted files files purely assume ES6
modules and should be able to work as-is once ES6 module integration for wasm is
completed.
Note that there aren't a ton of tools to pretend a wasm module is an ES6 module
at the moment but those should be coming soon! In the meantime a local
`wasm2es6js` hack was added to help make *something* work today. The README has
also been updated with instructions for interacting with this model.
