Wasm web support

[Anderssorby]

This adds:

• A wasm feature
• The ability to compile without fd-lock which makes it possible to compile to wasm

[gwenn]

https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html

If you’re building a non-end product, such as a rust library that other rust packages will depend on, put Cargo.lock in your .gitignore.

[johnchandlerburnham]

@gwenn Fixed. Tests pass locally for me, but if you can approve us to run workflows we can go through CI.

Also happy to keep/remove the Nix build from this PR (can move it to a separate PR if its of interest)

[gwenn]

nushell/nushell@65008bb ?
And are you sure that nix files are useful for a rust library ?

[johnchandlerburnham]

Not sure what nushell has to do with it, but there are advantages to having a nix build, such as portability for contributors. However, it also adds some complexity which you might not want.

Happy to keep or remove the nix build, up to you.

[gwenn]

And there is a related pending PR:
https://github.com/kkawakam/rustyline/pull/604/files#diff-2e9d962a08321605940b5a657135052fbcef87b5e360662bb527c96d9a615542
where FileHistory can be made optional.

[Anderssorby]

I've removed the nix stuff. The PR should be minimal now.

[Anderssorby]

@gwenn I guess it should be easy to integrate this into your PR?

[gwenn]

Except it is redundant with PR #604

[johnchandlerburnham]

It's not redundant. This PR is a minimal change of 25 lines which gets rustyline building on WASM. #604 is a >700 line change feature-level change which has been open for 2 months and has 2 of 5 tasks completed. It seems like merging this PR should be much easier, which will then let us use rustyline for our web repl: argumentcomputer/lurk-beta#57

That said, if you guys prefer to wait for #604 to have wasm support, that's fine with us, and we can just fork off a separate crate for our purposes in the meantime.

[gwenn]

• fix docs.rs features

[Anderssorby]

@gwenn I've fixed the comments and warnings. Let me know if there is anything else you want to change.

[Anderssorby]

@gwenn Any updates on this? It would be awkward to have to crate a new crate just to fix wasm compilation...

[gwenn]

I am wondering why not using #[cfg(not(target_arch = "wasm32"))] / #[cfg(target_arch = "wasm32")] ?

[Anderssorby]

I feel this is more explicit and meaningful. Maybe someone adds wasm (with wasi) support for this? Also one can now explicitly disable the fd-lock dependency for other cases too.

[gwenn]

Also one can now explicitly disable the fd-lock dependency for other cases too.

You mean like in PR #604 !

[samuelburnham]

Now that #604 is merged, rustyline compiles to wasm32-unknown-unknown on the master branch when the with-file-history feature is disabled. Thanks @gwenn! There are still a few warnings about unused variables/imports, but I think it's safe to close the PR.