SRFI 179: Nonempty Intervals and Generalized Arrays (Updated),

https://srfi.schemers.org/srfi-179/

an extension of SRFI 122, has been added as a module to LambdaNative, which the developers describe as

LambdaNative is an open-source (BSD licensed) cross-platform development environment written in Scheme (Gambit-C), supporting Android, iOS, BlackBerry 10, OS X, Linux, Windows, OpenBSD, NetBSD, FreeBSD and OpenWrt.

https://www.lambdanative.org/ https://github.com/part-cw/lambdanative

LambdaNative is written in Gambit Scheme.

Brad