Attribute Macro janetrs::janet_fn

#[janet_fn]

Macro that tranforms a high-level Janet function (fn(&mut [Janet]) -> Janet) to the thing the Janet C API is expecting (fn(i32, *mut janetrs::lowlevel::Janet) -> janetrs::lowlevel::Janet)

The optional argument catch adds code to catch Rust panics and transform them to Janet panics. This argument is ignored if the std feature is deactivated.

The optional argument arity adds a arity check for the function. It must receive the kind of arity check. These kinds are fix, for fixed arity, and range, for ranged or variadic arity. The fix kind receives a integer of the number of the parameters the Janet function must have and the range kind can receive two arguments, the first one if mandatory while the second one is optional, the first represents the minimal of arguments the Janet function have to receive and the second represents the maximum of arguments the Janet function can receive. If the maximum is not set for the range arity, the maximum check is disabled, allowing variadic arguments.

The optional arg check_mut_ref adds a check to see if the function received more than one reference to the same *mut pointer. This check is not the default because Janet Types act like types with interior mutability and the check is expensive, but if you want to make sure that your function never receives the same pointer more than once you can use this.

Usages:

• #[janet_fn]
• #[janet_fn(arity(fix(<N>)))] where N is an integer literal
• #[janet_fn(arity(range(<MIN> [, MAX])))] where MIN and MAX are integer literals
• #[janet_fn(catch)]
• #[janet_fn(check_mut_ref)]
• #[janet_fn(arity(<...>), check_mut_ref)] Combining both