Bulk Types with Class

Abstract

Bulk types --- such as lists, bags, sets, finitemaps, and priority queues --- are ubiquitous inprogramming. Yet many languages don't support themwell, even though they have received a great deal ofattention, especially from the databasecommunity. Haskell is currently among the culprits.This paper has two aims: to identify some of thetechnical difficulties, and to attempt to addressthem using Haskell's constructor classes.The paper can also be read as a concrete proposalfor new Haskell bulk type libraries.