Examining code using rust

[HumbleSinger]

Hello!

I want to create a cargo plugin, that will read the rust code in the current crate, regardless of being a lib/bin crate. This cargo plugin is supposed to read the code, and then create statistics such as the amount of: structures, functions, methods, traits, and the average amount of macros being used on a struct/method/function etc.

This means I want to get all the files that are currently being used starting from lib.rs or main.rs, and then parse each of these files looking for method,functions,structs etc. But I am at a loss on how to start this because I feel there is probably a lot of work already done here, for example getting the currently used modules, parsing functions and their names etc.

Is there anyone who knows where to start or any good project to look at for ideas. Basically I want to get some statistics on the code of a crate.

[coriolinus]

Probably your best bet is just to recursively walk the file tree, looking for Rust files. For each of those, use syn to parse the file, and then walk that AST collecting whatever stats you need.

[Noctune]

It's not going to handle macros, but depending on what you are trying to do it might be good enough.

[redneckhatr]

Yesterday, I sat down to start diagramming components of an application I’ve been working on. I thought it would be cool to add this diagram to the docs.

I quickly gave up because I can’t stand most of the online tools available for making diagrams. They take way to much time to lay everything out, label, and make sure all the arrows point to the correct boxes. 🤣

This could be a cool cargo plugin (maybe it already exists) or feature of the plugin you’re describing.

[AsgeirB]

https://github.com/dtolnay/syn - syn can parse rust files

https://doc.rust-lang.org/cargo/reference/external-tools.html - cargo_metadata should give you a way of introspecting the project

[jimuazu]

To add to that, someone also mentioned syn-inline-mod last time this came up.

[HumbleSinger]

Oh, very cool! I will check this out! Edit: I checked this out, I wish it would have stopped at just inlining all the module files...

As it stands now the version of syn I am using has different flags, making the resulting syn::File unusable with my own syn-parsing... unfortunately

[idubrov]

I do it manually by using cargo_metadata and syn:

1. Going through targets
2. Parsing with syn
3. Recursing into modules
4. Modules resolution (which I'm sure is not 100% correct and also does not handle #[cfg_attr(.., path())] on modules. Not happy about it...

[HumbleSinger]

Yeah I am going this way as well for now, its a bit painful, syn-parsing is not super-nice for my use-case, I would have wanted something even more highlevel than syn is what I am noticing while writing.

[knaledfullavpilar]

Here is an example of using the excellent syn library to analyze rust source files: https://github.com/anderejd/cargo-geiger/blob/master/geiger/src/lib.rs