Getting started

Install

Install the CLI and the language server from a checkout:

cargo install --path crates/renk --bin renk --bin renk-lsp

Scripts also need a nightly toolchain (rustup toolchain install nightly). The language server uses rust-analyzer from PATH when it is installed.

A first program

Save this as hello.rk:

pub fn sum_until(values: &[i32], limit: usize) -> i32:
    let mut index = 0
    let mut total = 0
    while index < limit:
        total += values[index]
        index += 1
    if total < 0 then 0 else total

pub fn main():
    println!("{sum_until(&[1, 2, 3], 2)}")

Then run renk transpile hello.rk -o hello.rs && rustc --edition 2024 hello.rs && ./hello, which prints 3.

The examples directory has more programs.

Commands

renk transpile input.rk -o output.rs           # Renk to Rust
renk transpile input.rk --source-map out.json  # also write a JSON source map
cat input.rk | renk                            # stdin to stdout
renk from-rust input.rs -o output.rk           # Rust to Renk
renk fmt input.rk -o input.rk                 # format
renk run                                        # transpile a crate, then cargo run
renk cargo test                                 # any cargo command
renk script tool.rk arg                        # run a single-file script
renk add tool.rk regex                         # add a script dependency
renk-lsp                                        # language server on stdio

Without -o, output goes to stdout. Run without an input while stdin is a terminal, renk prints its help.