Cargo projects

Put .rk files where Cargo expects .rs files. These commands transpile every .rk file under src, examples, tests, and benches, plus build.rk, to a .rs file beside it, then run the same Cargo command:

renk build
renk check
renk run
renk test
renk clippy
renk doc
renk bench
renk cargo ARGS...  # any other cargo command, as cargo ARGS...

A generated file starts with // @generated by renk; do not edit. and is rewritten only when its content changes. renk stops with an error instead of overwriting a .rs file without that header.

src/main.rk:

fn main():
    println!("{double(21)}")

fn double(n: i32) -> i32 = n * 2

#[cfg(test)]
mod tests:
    #[test]
    fn doubles():
        assert_eq!(super.double(2), 4)

renk run prints 42, and renk test runs doubles. mod name without a body declares a module file, as mod name; does in Rust.

Diagnostics

• Compiler diagnostics about generated files point at the .rk line and column and quote the .rk source. Diagnostics about other files print as rustc renders them.
• rustc’s suggested replacements are Rust code, so they are left out of .rk spans.
• --message-format=short prints src/main.rk:LINE:COLUMN: error: ... lines. --message-format=json... prints cargo’s JSON messages with spans, quoted lines, and rendered text moved to the .rk file.
• Panic messages and backtraces from renk run, renk test, and renk bench show .rk locations. A program whose output is a terminal still writes to a terminal.
• A name that does not resolve at a.b gets a help line saying how renk read the dot. See Limits.