instant-generics

This is a generic programming library based on type classes and type families first described by Chakravarty et al. (see http://www.cse.unsw.edu.au/~chak/project/generics/). The current release implements the extensions to support indexed datatypes described in: José Pedro Magalhães and Johan Jeuring. Generic Programming for Indexed Datatypes. Draft version, 2011. http://dreixel.net/research/pdf/gpid_draft.pdf