Help building a code browser

1

I'm toying with building a Rust code browser in Rust/wasm32.

We can assume that the to-be-browsed code builds fine under cargo build.

The feature I want most is jump to definition / jump to usage.

So if we have something like:

pub struct Foo {
  a: ...
  b: ...
}

pub fn main() {
  let c: Foo = ...

  c.b

then putting the cursor over the c of c.b should jump us to the let c: Foo = ..., and over the b of c.b should jump us to b: ....

This is nothing special, IntelliJ has this already.

My question is: do any existing open source crates do this? I want this data for all identifiers in all *.rs files in all crates. [I want to dump this data, not query it at runtime.]

Is there a simple (and fast) way to acquire this? I want something fast enough I can auto run after every successful cargo build. (so perferably it should not take much longer than a cargo build itself)

Thanks!

2
3

You can use rust-analyzer for this.

Either spin up the server and interact with it like a normal language client or use the ra_ap_hir crate to interact with it like a library.

The ra_ap_hir approach will probably be the most fruitful (you'll probably start at ra_ap_hir::Crate), but it requires more effort and a bit of understanding around rust-analyzer's architecture. I think you should be able to start things by creating your own database type and calling ra_ap_base_db::SourceDatabase::set_crate_graph() to tell it where your crates are.

A nice thing about this approach is you can keep the database instance around between builds (e.g. by making a long-running server that you ping after every build or change) and rust-analyzer's query caching will mean it doesn't need to re-analyze your entire dependency tree.

4 Likes
4

I hope this does not come off as entitled: Do you have sample code ? It does not have to do what you describe above, it just needs to use ra_ap_hir and does something .

I googled around, and not only could I not find sample code, I could not even find the github repo of ra_ap_hir.

5

Does that perform type checking? I don't think the requirement to discover a type definition based on a field access can be achieved without type checking.

6

No, ast-grep only searches ast nodes through tree-sitter without knowing the types.

7

The ra_ap_hir crate is part of the rust-analyzer repo.

Rust-analyzer has a pretty comprehensive test suite and a lot of the tests will run the entire pipeline. You should be able to find some good examples in there.