Enum SlotKind 

pub(crate) enum SlotKind {
    Sidecar(usize),
    Computed(Path),
    ScalarInt,
    ScalarReal,
    ScalarLogical,
    ScalarRaw,
    Conversion,
}

The kind of sidecar slot, determining how getter/setter FFI functions are generated.

Each kind maps to a different codegen strategy for reading and writing the slot through R’s .Call interface:

• Sidecar: a value in the external pointer’s protection list, validated with TryFromSexp::<T> on write and stored as R gave it.
• Scalars: a struct field, read into R with Rf_Scalar*, written with Rf_as*.
• Conversion: a struct field, converted with the IntoR/TryFromSexp traits.
• Computed: no field; a getter function of the Rust value, no setter.

Variants

Sidecar(usize)

Sidecar<T> field: the value at this position among the type’s Sidecar fields, kept in the external pointer’s protection list (getter returns it, setter validates value as a T and stores it there).

Computed(Path)

Computed marker field: the getter calls this function, a fn(&Self) -> impl IntoR (a leading Self already replaced by the struct’s name), on the live Rust value; there is no setter (#1883).

ScalarInt

Scalar struct field i32 (or i16/i8), returned as a length-1 integer.

ScalarReal

Scalar struct field f64 (or f32), returned as a length-1 double.

ScalarLogical

Scalar struct field bool (or Rbool), returned as a length-1 logical.

ScalarRaw

Scalar struct field u8, returned as a length-1 raw.

Conversion

Conversion type – uses IntoR/TryFromSexp traits for arbitrary Rust types.

Trait Implementations

impl Clone for SlotKind

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for SlotKind

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for SlotKind

#[doc(hidden)]

fn assert_fields_are_eq(&self)

🔬This is a nightly-only experimental API. (derive_eq_internals)

#[doc(hidden)]

fn assert_receiver_is_total_eq(&self)

👎Deprecated since 1.95.0:

implementation detail of #[derive(Eq)]

impl PartialEq for SlotKind

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for SlotKind

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 56 bytes

Size for each variant:

• Sidecar: 16 bytes
• Computed: 56 bytes
• ScalarInt: 0 bytes
• ScalarReal: 0 bytes
• ScalarLogical: 0 bytes
• ScalarRaw: 0 bytes
• Conversion: 0 bytes