Module altrep_impl 

ALTREP implementation utilities.

This module provides helper functions used by the declarative macros generated for ALTREP classes. The proc-macro derives (#[derive(AltrepInteger)] etc.) lower to invocations of impl_alt*_from_data! macros which expand to code that references items in this module via $crate::altrep_impl::* paths.

Use crate::altrep_data1_as (re-exported from externalptr) to extract data from an ALTREP’s data1 slot.

Layout

• macros — #[macro_export] declarative macros (impl_alt*_from_data! and their __impl_* helpers).
• builtins — crate-private meta-macro + invocations for Vec<T> / Box<[T]> / Cow<T> / Range<T> ALTREP families.
• arrays — const-generic [T; N] ALTREP impls.
• static_slices — hand-written &'static [T] ALTREP impls.

Modules

arrays

ALTREP for owned const-generic arrays.

buffers

Registered native buffers with value duplication and retained allocations.

builtins

Built-in ALTREP class instantiations for Vec<T>, Box<[T]>, Cow<T>, and Range<T>.

macros

Declarative macros generating ALTREP trait implementations.

shared_slices

Shared slice owners with coordinated COW and duplicate policies.

static_slices

ALTREP impls for &'static [T].

Functions

altlist_set_elt 👻 ^⚠

Set_elt for bridge-generated list ALTREPs; R’s default raises an error.

altrep_region_buf^⚠

Create a mutable slice from an ALTREP get_region output buffer pointer.

altstring_cache 🔒 ^⚠

Return a bridge string ALTREP’s data2 element cache, allocating it on first use.

altstring_cache_written 🔒 ^⚠

Whether R has stored a value into a string ALTREP’s cache.

altstring_cached_elt 🔒 ^⚠

Read cache slot i, computing it from the Rust data on first use.

altstring_dataptr 👻 ^⚠

Dataptr for bridge-generated string ALTREPs: fill every cache slot and return the cache’s pointer. A writable request marks the cache written first (see altstring_cache_written), since R writes through it.

altstring_elt 👻 ^⚠

Elt for bridge-generated string ALTREPs: each element is computed once.

altstring_set_elt 👻 ^⚠

Set_elt for bridge-generated string ALTREPs; R’s default raises an error.

checked_mkchar^⚠

Create a CHARSXP from a Rust string, with checked length conversion.

duplicate_altrep_data2 👻 ^⚠

Copy a bridge ALTREP’s data2 for a Duplicate callback.

duplicate_altrep_owner 👻 ^⚠

Clone a derive-generated ALTREP owner while preserving its current R cache. R’s default DuplicateEX copies attributes and object flags after this hook.

mark_altstring_written 🔒 ^⚠

Mark a string ALTREP’s cache written; see altstring_cache_written.

new_altstring_cache 🔒 ^⚠

Allocate a string cache of length n with every slot empty (C NULL).