Module markers 

Marker traits for proc-macro derived types. Marker traits for proc-macro derived types.

These marker traits identify types that have been derived with specific proc-macros. They enable compile-time type checking and blanket implementations.

Pattern

Each derive macro generates an impl of its corresponding marker trait:

Derive Macro	Marker Trait
#[derive(PreferList)]	crate::markers::PrefersList
#[derive(PreferExternalPtr)]	crate::markers::PrefersExternalPtr
#[derive(PreferRNativeType)]	crate::markers::PrefersRNativeType
#[derive(PreferDataFrame)]	crate::markers::PrefersDataFrame

Traits

PrefersDataFrame

Marker trait for types that should be converted to R data frames via IntoR.

PrefersExternalPtr

Marker trait for types that prefer ExternalPtr conversion.

PrefersList

Marker trait for types that should be converted to R lists via IntoR.

PrefersRNativeType

Marker trait for types that prefer native SEXP conversion.

WidensToF64

Marker trait for types that can widen to f64 without loss.

WidensToI32

Marker trait for types that can widen to i32 without loss.