syn-file-expand

This library allows you to load full source code of multi-file crates into a single syn::File.

Features:

• Based on syn crate.
• Handling #[path] attributes
• Handling #[cfg] where it affects modules to filesystem mapping
• There is both a lower-level IO-less function and a simpler to use function.

Start exploring the library from the [read_full_crate_source_code] function.

Bonus: CLI tool

syn-file-expand-cli tool expands Rust sources, like cargo expand, but without macro expansion, only for modules. rustc is not involved. Filtering through rustfmt is adviced for debugging use case.

$ syn-file-expand-cli src/lib.rs | rustfmt
# ! [doc = include_str ! ("../README.md")]
#![forbid(unsafe_code)]
...
mod attrs {
    use super::AttrParseError;
    ...
}
mod expand_impl {
    use crate::{attrs, Error, ErrorCase, Resolver};
    ...
}

$ syn-file-expand-cli --help
Usage: target/q/debug/syn-file-expand-cli [OPTIONS]

Reads rust source file, including referred modules and expands them into a single source with all modules inline
Apart from respective dedicated command line arguments, conditional paths like
`#[cfg_attr(feature="qqq"),path=...)` are resolved using
environment variables like SYN_FILE_EXPAND_FEATURE_QQQ=1
Other influential envvars: SYN_FILE_EXPAND_DEBUGVARS=1 SYN_FILE_EXPAND_DEFAULTTRUE=1

Positional arguments:
  input_file                 Input Rust source file to start crawling from

Optional arguments:
  -h, --help
  -l, --loopify              Convert all blocks and expressions to `loop{}`s.
  -D, --undoc                Stip all documentation attributes.
  -T, --cfg-true-by-default  Assume all `#[cfg]`s and `#[cfg_attr]`s are true.
  -c, --cfg CFG              Set this cfg check result to true.
  -u, --unset-cfg UNSET-CFG  In `--cfg-true-by-default` mode, explicitly unset given cfg expression outcome.
  -d, --debug-cfg            Print each encountered cfg check to stderr, in form suitable for `--cfg` parameter.
  -o, --output OUTPUT        Use given file for output instead of stdout

There is a Github release with the tool pre-built for various platforms.
You can also install the tool using cargo install syn-file-expand-cli.