I've added SRFI 231, Intervals and Generalized Arrays, to the Gambit source tree: https://srfi.schemers.org/srfi-231/ SRFI 231 is an updated and improved version of SRFI 179. There are a few incompatible changes between the two SRFIs, see https://srfi.schemers.org/srfi-231/srfi-231.html#Rationale As SRFI 231 improves SRFI 179 in almost every way, I intend to remove SRFI 179 support from the GitHub repository soon. Brad