Calling Rust code from Tcl

This is a demo of how to build a Rust library which can be invoked from within a Tcl program.

The tcltk library is used to expose Rust functions as Tcl commands. The top-level src/lib.rs file provides the Tcl interface, while the actual Rust API lives in src/greeter.rs.

Building and running

Using the Nix shell for development is recommended. There are two development shells provided by flake.nix.

Generally, nix develop is what you'll want. It will give you:

• A Rust compiler and associated tooling
• tclsh
• The final product, a Tcl package called greeter, which you can package require as you'd expect.

From within this default dev shell, you can experiment with calls to greeter and execute the sample test.tcl program:

~/src/rust-from-tcl$ nix develop
fa-BenBurwell:rust-from-tcl ben.burwell$ tclsh test.tcl 
Hello, world!
Bonjour, world!
Hola, world!

If you need to tweak things about the Rust build without depending on a finished Tcl package (e.g. to fix something broken), you can use nix develop '.#rustOnly'. You'll still get the Rust toolchain, but you won't be able to package require greeter from Tcl.