C

chicken-scheme

Immutable Lists (see: https://srfi.schemers.org/srfi-116/srfi-116.html)

SRFI 128: Comparators (reduced)

Sets and Bags (see: https://srfi.schemers.org/srfi-113/srfi-113.html)

CHICKEN Scheme package and project manager, written in Rust.

Transducers for working with foldable data types.

Composable Scheme macro system based on the CK abstract machine

Flexible Scheme objects with message passing and prototypes