This commit rejiggers some documentation of `wasm-bindgen` in a few
significant ways:
* The main landing page now has text and links to the Game of Life
tutorial and `wasm-pack`.
* The "whirlwind tour" was deleted as it wasn't really serving any
purpose that the Game of Life plus the later references weren't already
serving.
* The "no modules" example was renamed to "without a bundler"
* A dedicated section on "Deployment" was added which replaces the
previous "No ES Modules" page. This is hopefully more descriptive and
also prominently mentions the various options for deployment.
This commit moves `wasm-bindgen` the CLI tool from internally using
`parity-wasm` for wasm parsing/serialization to instead use `walrus`.
The `walrus` crate is something we've been working on recently with an
aim to replace the usage of `parity-wasm` in `wasm-bindgen` to make the
current CLI tool more maintainable as well as more future-proof.
The `walrus` crate provides a much nicer AST to work with as well as a
structured `Module`, whereas `parity-wasm` provides a very raw interface
to the wasm module which isn't really appropriate for our use case. The
many transformations and tweaks that wasm-bindgen does have a huge
amount of ad-hoc index management to carefully craft a final wasm
binary, but this is all entirely taken care for us with the `walrus`
crate.
Additionally, `wasm-bindgen` will ingest and rewrite the wasm file,
often changing the binary offsets of functions. Eventually with DWARF
debug information we'll need to be sure to preserve the debug
information throughout the transformations that `wasm-bindgen` does
today. This is practically impossible to do with the `parity-wasm`
architecture, but `walrus` was designed from the get-go to solve this
problem transparently in the `walrus` crate itself. (it doesn't today,
but this is planned work)
It is the intention that this does not end up regressing any
`wasm-bindgen` use cases, neither in functionality or in speed. As a
large change and refactoring, however, it's likely that at least
something will arise! We'll want to continue to remain vigilant to any
issues that come up with this commit.
Note that the `gc` crate has been deleted as part of this change, as the
`gc` crate is no longer necessary since `walrus` does it automatically.
Additionally the `gc` crate was one of the main problems with preserving
debug information as it often deletes wasm items!
Finally, this also starts moving crates to the 2018 edition where
necessary since `walrus` requires the 2018 edition, and in general it's
more pleasant to work within the 2018 edition!
This commit migrates all our examples to using `wasm-pack build` to
compile their code and run `wasm-bindgen`. This should make it a bit
easier to understand the examples as there's less to follow during the
build step.
Webpack projects are all using `@wasm-tool/wasm-pack-plugin` as well so
the build step is simple `npm run serve`. Other examples which retain
`build.sh` are just using `wasm-pack build` now
