Converting from Rust

renk from-rust converts Rust to Renk:

renk from-rust src/lib.rs -o src/lib.rk
renk from-rust src/lib.rs -o src/lib.rk --aggressive

The output uses dotted paths, [T] generics, fn f() -> T = expr, inferred ;, and if c then a else b only where the result transpiles back to the same Rust tokens. Format arguments that each fill one placeholder in order are inlined: format!("{}", cli.url) becomes format!("{cli.url}"). :: paths become dotted paths where that reads back the same: std::env::args() becomes std.env.args(), while Config::DEFAULT.len() keeps its ::. A turbofish call becomes name[...](, as in s.parse[i32](), and a turbofish on a CamelCase path becomes Name[...], as in Vec[String].new(); other turbofish stays Rust. Index-then-call receivers and path value receivers are parenthesized, as in (handlers[i])() and (std.cmp.Ordering.Less).reverse().

--aggressive also accepts rewrites that keep the Rust tokens but not their line layout, such as multi-line if/else value chains.

Comments, string literals, and macro bodies are kept as written. Anything Renk has no indentation form for, such as a { block holding a match scrutinee, stays Rust syntax.

Round-trip tests

The repository tests the round trip Rust -> Renk -> Rust on a corpus of Rust files and on pinned real crates. For each real crate, the round-tripped crate must compile, keep every comment, and produce the same MIR as the original after normalizing source locations, local and basic block numbering, and unit temporaries. MIR is compared with default features, with every feature, and for the unit tests, wherever the original builds that way.

cargo test -p renk --test real_crates -- --ignored --nocapture

The test downloads the crates from crates.io and needs a nightly toolchain for --emit=mir.