cljrs build-native

Compile the project’s embedded Rust crate to a shared library so that cljrs run and cljrs repl can load native functions at startup.

cljrs build-native [--release]

This command reads the :rust key from the nearest cljrs.edn, runs cargo build inside the declared crate directory, and prints the path of the resulting library to stdout.

Options

--release

Build in release mode (cargo build --release) instead of the default debug mode. Use this when profiling or shipping.

What it does

1. Locates cljrs.edn by walking up the directory tree.
2. Reads :rust :crate (the directory containing the user’s Cargo.toml) and :rust :init (the fully-qualified Rust path to the init function).
3. Derives the crate name from the first :: segment of the init path — e.g. "my_project::cljrs_init" → my_project.
4. Runs cargo build [--release] in the crate directory.
5. Prints the output library path on success:
   • Linux: target/debug/libmy_project.so
   • macOS: target/debug/libmy_project.dylib
   • Windows: target/debug/my_project.dll

Auto-loading

Once the library exists, cljrs run and cljrs repl load it automatically on startup — no flags required. If the library is absent (not yet built or deleted), a warning is printed but the interpreter continues; calls to unregistered native functions will produce a runtime error.

Example

# Build the native library
cljrs build-native

# Now run Clojure code that calls native functions
cljrs run src/main.cljrs

See Rust Interop for a complete walkthrough.