SRFI 289: Unordered sets and bags

by Wolfgang Corcoran-Mathe (text and test suite), Peter McGoron (sample implementation), and John Cowan (author of SRFI 113)

status: draft (2026-11-14)

keywords: Data Structure

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Abstract

Sets and bags (also known as multisets) are unordered collections that contain only objects of a type given by a collection’s SRFI 128 comparator. Every element of a set is unique (in the sense of the set’s comparator), but bags can contain any number of duplicate elements. This SRFI is a revision of SRFI 113 that fixes several infelicities and is more consistent with related SRFIs.