Struct AltrepFamilyConfig 

struct AltrepFamilyConfig<'a> {
    family_name: &'a str,
    dataptr_macro: Option<(&'a str, Option<TokenStream>)>,
    string_dataptr: bool,
    subset: bool,
    methods_macro: &'a str,
    inferbase_macro: &'a str,
    default_guard: &'a str,
    materializing_dataptr_macro: &'a str,
}

Per-family configuration controlling low-level code generation for an ALTREP type family.

Each ALTREP family (integer, real, logical, raw, string, complex, list) has a distinct set of runtime macros for trait implementations and different capabilities (e.g., only some families support dataptr or subset). This struct captures those differences so AltrepAttrs::generate_lowlevel can emit the correct code.

Fields

family_name: &'a str

Human-readable family name used in option-validation error messages (e.g., "AltrepInteger").

dataptr_macro: Option<(&'a str, Option<TokenStream>)>

If this family supports a typed dataptr materialization macro, the tuple contains:

• The macro name (e.g., "__impl_altvec_dataptr")
• An optional element type token stream (e.g., i32 for integer, f64 for real)

None means this family does not have a typed dataptr macro (e.g., list).

string_dataptr: bool

Whether this family supports the string-specific dataptr materialization macro (__impl_altvec_string_dataptr). Only true for the String family.

subset: bool

Whether this family supports the subset option for Extract_subset method registration. false for List (which rejects subset and dataptr).

methods_macro: &'a str

Name of the internal macro for type-specific method implementations (e.g., "__impl_altinteger_methods" for integer).

inferbase_macro: &'a str

Name of the impl_inferbase_*! macro that provides InferBase for this family (e.g., "impl_inferbase_integer").

default_guard: &'a str

Default guard mode for this family when no explicit guard is specified. String family uses RUnwind because elt/dataptr call R APIs (Rf_mkCharLenCE). All families now default to RUnwind.

materializing_dataptr_macro: &'a str

Family-specific materializing dataptr macro (e.g. "__impl_altvec_integer_dataptr"). The default/serialize arms use it to install the trivial AltrepDataptr + materializing AltVec.

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: 136 bytes