Module factor 

Factor support for enum ↔ R factor conversions.

Provides the RFactor trait for converting Rust enums to/from R factors. Use #[derive(RFactor)] on C-style enums to auto-generate the implementation.

Example

use miniextendr_api::RFactor;

#[derive(Copy, Clone, RFactor)]
enum Color { Red, Green, Blue }

#[miniextendr]
fn color_name(c: Color) -> &'static str {
    match c {
        Color::Red => "red",
        Color::Green => "green",
        Color::Blue => "blue",
    }
}

Factor support for enum ↔ R factor conversions.

R factors are integer vectors with a levels attribute (character vector) and a class attribute set to "factor". The integer payload uses 1-based indexing into the levels, with NA_INTEGER for missing values.

Usage

use miniextendr_api::RFactor;

#[derive(Copy, Clone, RFactor)]
enum Color { Red, Green, Blue }

// Enum values convert to/from R factors automatically
#[miniextendr]
fn describe(c: Color) -> &'static str {
    match c {
        Color::Red => "red",
        Color::Green => "green",
        Color::Blue => "blue",
    }
}

Structs

Factor

A borrowed view into an R factor’s integer indices.

FactorMut

A mutable borrowed view into an R factor’s integer indices.

FactorOptionVec

Wrapper for Vec<Option<T: RFactor>> with NA support.

FactorVec

Wrapper for Vec<T: UnitEnumFactor> enabling IntoR/TryFromSexp.

Statics

FACTOR_CLASS 🔒

Traits

RFactor

Trait for mapping Rust enums to R factors.

UnitEnumFactor

Trait implemented by unit-only enums derived via #[derive(DataFrameRow)].

Functions

build_factor

Build a factor SEXP from indices and a levels STRSXP.

build_factor_with_levels

Build a factor SEXP from indices and level names in a single call.

build_levels_sexp

Build a levels STRSXP of UTF-8 CHARSXPs.

build_levels_sexp_cached

Build a levels STRSXP and preserve it permanently (for caching).

build_levels_sexp_protected 🔒

Keep the container rooted while each level’s CHARSXP is allocated.

code_not_a_level 🔒

The reason a factor code does not name one of the levels (a malformed factor: validate_factor_levels has already checked the level set).

factor_class_sexp 🔒

factor_from_sexp

Convert an R factor SEXP to a single enum value.

factor_option_vec_from_sexp 🔒

Convert an R factor SEXP to a Vec of Option enum values (NA → None).

factor_vec_from_sexp 🔒

Convert an R factor SEXP to a Vec of enum values. Every NA and every code outside the levels is reported, with its position.

read_factor_codes 🔒

Read every code of a factor through elt, batching every failing element (its reason and 1-based position) into one error instead of stopping at the first.

unit_factor_option_vec_from_sexp

Convert an R factor SEXP to a Vec<Option<T>> using UnitEnumFactor (NA → None).

validate_factor_levels 🔒

Validate that a factor has the expected levels.