Enum CoercionMapping 

pub(crate) enum CoercionMapping {
    Scalar {
        r_native: TokenStream,
        target: TokenStream,
    },
    Vec {
        r_native_elem: TokenStream,
        target_elem: TokenStream,
    },
}

Result of coercion analysis for a type. Contains the R native type to extract from SEXP and the target type to coerce to.

Variants

Scalar

Scalar coercion: extract R native type, coerce to target.

Fields

r_native: TokenStream

The R-native scalar type to extract from the SEXP (e.g., i32 for R integers, f64 for R reals). This is the type that R stores internally.

target: TokenStream

The Rust target type to coerce into (e.g., u16, bool, f32).

Vec

Vec coercion: extract R native slice, coerce element-wise to Vec<target>.

Fields

r_native_elem: TokenStream

The R-native element type of the source slice (e.g., i32 for integer vectors, f64 for real vectors).

target_elem: TokenStream

The Rust target element type for the resulting Vec (e.g., u16, bool, f32).

Implementations

impl CoercionMapping

pub(crate) fn from_type(ty: &Type) -> Option<Self>

Determines the coercion mapping for a Rust type, if it needs coercion from an R-native type.

Returns None if the type is already R-native (i32, f64, String, etc.) or is not a recognized coercible type.

Recognized coercions

• Scalar integer-like (u16, i16, i8, u32, u64, i64, isize, usize): coerced from i32 (R’s native integer type).
• Scalar bool: coerced from i32 (R’s logical vectors use i32 internally).
• Scalar f32: coerced from f64 (R’s native real type).
• Vec<T> variants: element-wise coercion from the corresponding R-native slice type.

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: 72 bytes

Size for each variant:

• Scalar: 64 bytes
• Vec: 64 bytes