2026-02-19 11:08:20 +00:00
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use std::ffi::{CStr, c_char};
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Call Rust from Haskell with `cargo-cabal` and `hs-bindgen`
See https://sraka.xyz/posts/hs-bindgen-introduction.html.
For now, this is a shell-based workflow, rather than using Nix to build everything, i.e. `nix develop` works but `nix build` doesn't. And `cargo build` has to be called manually to create the C library, rather than `cabal` being clever enough to invoke it itself.
We ran `cargo cabal init` from the `rust` directory (`nix shell github:yvan-sraka/cargo-cabal`), which generated `hsbindgen.toml` (which we use), and `Setup.lhs` (which just added `extra-lib-dirs`, and with the wrong paths, so we dspecify those statically instead in `garnet.cabal`). We also follow its advice to use `staticlib`.
Also, after we ran the first `cargo build` (requiring a `mkdir rust/src` before it would run), we took the generated the Haskell file, and moved the main contents in to `Main.hs` manually.
2026-02-18 15:49:08 +00:00
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2026-02-19 11:08:20 +00:00
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fn say_hello(name: &str) {
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Call Rust from Haskell with `cargo-cabal` and `hs-bindgen`
See https://sraka.xyz/posts/hs-bindgen-introduction.html.
For now, this is a shell-based workflow, rather than using Nix to build everything, i.e. `nix develop` works but `nix build` doesn't. And `cargo build` has to be called manually to create the C library, rather than `cabal` being clever enough to invoke it itself.
We ran `cargo cabal init` from the `rust` directory (`nix shell github:yvan-sraka/cargo-cabal`), which generated `hsbindgen.toml` (which we use), and `Setup.lhs` (which just added `extra-lib-dirs`, and with the wrong paths, so we dspecify those statically instead in `garnet.cabal`). We also follow its advice to use `staticlib`.
Also, after we ran the first `cargo build` (requiring a `mkdir rust/src` before it would run), we took the generated the Haskell file, and moved the main contents in to `Main.hs` manually.
2026-02-18 15:49:08 +00:00
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println!("Hello from Rust, {name}!");
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}
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2026-02-19 11:08:20 +00:00
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#[unsafe(no_mangle)]
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extern "C" fn hello(c: *const c_char) -> () {
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say_hello(unsafe { CStr::from_ptr(c) }.to_str().unwrap())
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}
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