wolfram-export

Unified #[export] runtime for Wolfram LibraryLink functions. Choose the calling convention you need via Cargo features.

Calling conventions (features)

[dependencies]
wolfram-export = { version = "0.6", features = ["wstp"] }

use wolfram_export::export;

#[export]
fn add(a: i64, b: i64) -> i64 {
    a + b
}

#[export(wstp)]
fn echo(args: Vec<wolfram_expr::Expr>) -> wolfram_expr::Expr {
    args.into_iter().next().unwrap_or(wolfram_expr::Expr::from(0))
}

For full manual control over marshaling, use #[export(margs)] with an args = (..)/ret = .. signature annotation (spliced into wolfram_expr::expr! calls, so wolfram-expr must be a direct dependency to use them):

use wolfram_export::{export, sys::MArgument};
use wolfram_library_link::FromArg;

#[export(margs, args = (::Real, ::Real), ret = ::Real)]
fn raw_add(args: &[MArgument], ret: MArgument) {
    let a = unsafe { f64::from_arg(&args[0]) };
    let b = unsafe { f64::from_arg(&args[1]) };
    unsafe { *ret.real = a + b; }
}

Omitting args/ret still compiles, but defaults the generated LibraryFunctionLoad type spec to LinkObject/LinkObject (which a raw MArgument function doesn't actually accept) and emits a compile-time warning telling you to annotate it.

#[export(margs)] is also how you reach types with no FromArg/IntoArg impl, like SparseArray — read/write the raw MArgument.sparse (MSparseArray) pointer and drive the WolframSparseLibrary_Functions C API (exposed as rtl::MSparseArray_*/rtl::MTensor_* in wolfram-library-link) directly. See margs_sparse_array_merge in wolfram-examples-internal/src/margs.rs for a worked example.

The automate-function-loading-boilerplate feature (on by default) emits the __wolfram_manifest__ C-ABI symbol that lets the paclet loader discover all exported functions automatically.

Changelog

See docs/CHANGELOG.md.