Features | miniextendr

🔗Cargo Features

miniextendr uses cargo features to gate optional functionality:

Feature	Description
`serde_r`	Direct Rust-R serialization via serde
`serde_full`	Both JSON and native R serialization
`worker-thread`	Dedicated worker thread for Rust code
`default-worker`	Implies `worker-thread`, makes it the default
`nonapi`	Access to non-API R functions (`DATAPTR`, etc.)
`rayon`	Parallel computation via rayon
`materialization-tracking`	ALTREP materialization diagnostics

🔗Derive Macros

Derive	Purpose
`#[derive(ExternalPtr)]`	Wrap struct as R external pointer
`#[derive(DataFrameRow)]`	Convert struct to/from data frame row
`#[derive(Vctrs)]`	Generate vctrs-compatible class
`#[derive(RFactor)]`	Map enum variants to R factor levels
`#[derive(PreferExternalPtr)]`	Prefer ExternalPtr over data conversion
`#[derive(PreferDataFrame)]`	Prefer DataFrame over ExternalPtr

🔗Attribute Options

The #[miniextendr] attribute supports many options:

// Function-level
#[miniextendr]                       // Basic export
#[miniextendr(strict)]               // Reject lossy conversions
#[miniextendr(internal)]             // @keywords internal
#[miniextendr(noexport)]             // Suppress @export
#[miniextendr(unwrap_in_r)]          // Return Result errors as R values
#[miniextendr(default = "value")]    // Default parameter value

// Impl-level (class systems)
#[miniextendr]                       // Env style (default)
#[miniextendr(r6)]                   // R6 class
#[miniextendr(s3)]                   // S3 methods
#[miniextendr(s4)]                   // S4 class
#[miniextendr(s7)]                   // S7 class
#[miniextendr(label = "name")]       // Label for multiple impl blocks

🔗Variadic Arguments (Dots)

R’s ... becomes &Dots in Rust:

use miniextendr_api::dots::Dots;

#[miniextendr]
pub fn count_args(_dots: &Dots, ...) -> i32 {
    _dots.len() as i32
}

Validate dot structure with typed_list!:

#[miniextendr(dots = typed_list!(x: i32, y: f64))]
pub fn structured_dots(_dots: &Dots, ...) -> f64 {
    dots_typed.x as f64 + dots_typed.y
}

🔗Factors (Enums)

Map Rust enums to R factors:

#[derive(miniextendr_api::RFactor)]
pub enum Color { Red, Green, Blue }

#[miniextendr]
pub fn describe_color(color: Color) -> &'static str {
    match color {
        Color::Red => "warm",
        Color::Green | Color::Blue => "cool",
    }
}