Struct AsNamedList 

pub struct AsNamedList<T>(pub T);

Wrap a tuple pair collection and convert it to a named R list (VECSXP).

Preserves insertion order and allows duplicate names (sequence semantics).

Supported input types

Input	Bounds
Vec<(K, V)>	K: AsRef<str>, V: IntoR
[(K, V); N]	K: AsRef<str>, V: IntoR
&[(K, V)]	K: AsRef<str>, V: Clone + IntoR

GC safety — use typed values, never raw SEXP (#1030)

Prefer typed value types (i32, String, Vec<T>, …) over raw crate::SEXP. With a typed V, each value’s into_sexp() runs inside AsNamedList::into_sexp, immediately before the value is protected and placed into the list — no allocation ever fires while a sibling value sits unprotected.

A raw SEXP value (V = SEXP) is GC-fragile and must not be used. The caller has to build the SEXP values in an earlier frame (each into_sexp() allocates) and then hand them to AsNamedList; the deferred from_raw_pairs runs later, in the generated wrapper, so there is no call site at which a ProtectScope can span both value construction and the deferred list build. The internal protection added in into_sexp (below) closes the receipt → from_raw_pairs window but cannot retroactively protect values that were already built and unrooted in the caller — that construction window is the latent use-after-free. Stable Rust cannot exclude one concrete type from a V: IntoR blanket, so this is enforced by convention (and the MXL302 lint on the into_sexp()-in-vec! idiom) rather than the type system; passing typed values sidesteps the hazard entirely.

Example

#[miniextendr]
fn make_config() -> AsNamedList<Vec<(String, i32)>> {
    AsNamedList(vec![
        ("width".into(), 100),
        ("height".into(), 200),
    ])
}
// In R: make_config() returns list(width = 100L, height = 200L)

Tuple Fields

0: T

Trait Implementations

impl<T: Clone> Clone for AsNamedList<T>

fn clone(&self) -> AsNamedList<T>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for AsNamedList<T>

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

Formats the value using the given formatter.

impl<T> From<T> for AsNamedList<T>

fn from(value: T) -> Self

Converts to this type from the input type.

impl<K: AsRef<str>, V: IntoR> IntoR for AsNamedList<Vec<(K, V)>>

type Error = Infallible

The error type for fallible conversions.

fn try_into_sexp(self) -> Result<SEXP, Self::Error>

Try to convert this value to an R SEXP.

unsafe fn try_into_sexp_unchecked(self) -> Result<SEXP, Self::Error>

Try to convert to SEXP without thread safety checks.

fn into_sexp(self) -> SEXP

Convert this value to an R SEXP, panicking on error.

unsafe fn into_sexp_unchecked(self) -> SEXP

where Self: Sized,

Convert to SEXP without thread safety checks, panicking on error.

impl<K: AsRef<str>, V: IntoR, const N: usize> IntoR for AsNamedList<[(K, V); N]>

type Error = Infallible

The error type for fallible conversions.

fn try_into_sexp(self) -> Result<SEXP, Self::Error>

Try to convert this value to an R SEXP.

unsafe fn try_into_sexp_unchecked(self) -> Result<SEXP, Self::Error>

Try to convert to SEXP without thread safety checks.

fn into_sexp(self) -> SEXP

Convert this value to an R SEXP, panicking on error.

unsafe fn into_sexp_unchecked(self) -> SEXP

where Self: Sized,

Convert to SEXP without thread safety checks, panicking on error.

impl<K: AsRef<str>, V: Clone + IntoR> IntoR for AsNamedList<&[(K, V)]>

type Error = Infallible

The error type for fallible conversions.

fn try_into_sexp(self) -> Result<SEXP, Self::Error>

Try to convert this value to an R SEXP.

unsafe fn try_into_sexp_unchecked(self) -> Result<SEXP, Self::Error>

Try to convert to SEXP without thread safety checks.

fn into_sexp(self) -> SEXP

Convert this value to an R SEXP, panicking on error.

unsafe fn into_sexp_unchecked(self) -> SEXP

where Self: Sized,

Convert to SEXP without thread safety checks, panicking on error.

Layout

Note: Unable to compute type layout, possibly due to this type having generic parameters. Layout can only be computed for concrete, fully-instantiated types.