Module native 

The native function binding system - Module, NativeFn, and the IntoNativeFn / FromValue / IntoValue trait machinery.

How it works

Stdlib functions are plain Rust functions. The IntoNativeFn trait (implemented by a macro for up to 10 arguments) wraps them into NativeFn closures that handle arity checking and argument extraction automatically.

Two variants exist:

• Infallible (IntoNativeFn<(A1, A2, ...)>) - for functions that return R: IntoValue
• Fallible (IntoNativeFn<(Fallible<(A1, A2, ...)>,)>) - for functions returning Result<R, Error>
• Spanned (IntoNativeFn<(Spanned<(A1, A2, ...)>,)>) - fallible functions that also receive the call Span

Example

use rl_lang::interpreter::{evaluator::Evaluator, native::Module};

fn my_fn(_: &mut Evaluator, x: i64, y: i64) -> i64 { x + y }
Module::new("math").with_function("add", my_fn);

Macros

impl_into_native_fn 🔒

impl_into_native_fn_spanned 🔒

Structs

Fallible

Marker type for fallible native functions (returning Result<R, Error>).

Module

A named collection of NativeFns, optionally containing sub-Modules.

Spanned

Marker type for spanned fallible native functions (also receiving the call Span).

Traits

FromValue

Converts a Value into a typed Rust value, or returns a runtime error. Implemented for i64, f64, String, bool, char, Vec<T>, and Value itself.

IntoNativeFn

Wraps a typed Rust function into a NativeFn with automatic arity checking and argument extraction. Implemented by macro for 0–10 arguments.

IntoValue

Converts a typed Rust value into a Value. Implemented for () (→ Null), i64, f64, String, bool, char, Vec<T>, and Value.

ValueType

Extracts the static TypeAnnotation for a Rust type. Used by IntoValue for Vec<T> to set the array’s items_type.

Type Aliases

NativeFn

A thread-safe, heap-allocated native function callable from rl.