Tools

Formatter

renk fmt lays out a file the way rustfmt lays out Rust: indentation, line breaks, and spacing. It runs rustfmt --edition 2024 on the generated Rust, so it needs rustfmt (rustup component add rustfmt) and follows the rustfmt.toml of the working directory. Comments, blank lines, and string contents stay. A script keeps its #! line and frontmatter. An item that cannot be formatted without changing its Rust keeps its lines, with trailing whitespace trimmed.

renk fmt src/main.rk -o src/main.rk
renk fmt --check src/*.rk    # prints a diff and exits with 1 if a file is not formatted

Source maps

renk transpile FILE.rk --source-map MAP.json also writes a JSON tree of the Renk syntax nodes, each with its source line, column, and text and the generated Rust lines it became.

Web runner

podman compose up --build serves the web editor at http://localhost:8080. It transpiles in the browser and compiles and runs snippets with the image’s rustc. just web starts the editor from a checkout.

• The image builds the web UI at build time and bundles the renk CLI and a small renk-web HTTP server. Deno is used only in the build stage.
• The runner bundles trpl 0.3.0, so snippets can use helpers such as trpl::block_on without a Cargo manifest.
• The service binds to 127.0.0.1:8080 on the host. The container is read-only except for /tmp, where snippets are compiled and run under RENK_RUN_TIMEOUT_MS.
• Run requests are limited by default to 64 KiB of Rust source, 256 KiB of captured output, two concurrent runs, and ten runs per minute.
• Behind a Cloudflare Tunnel, put Cloudflare Access and a /api/run rate limit in front of the service.