HAP is a homological algebra library for use with the GAP computer
algebra system, and is still under development. Its initial focus is on
computations related to the cohomology of groups. Both finite and
infinite groups are handled, with emphasis on integral coefficients.
Recent additions include some functions for computing homology of
crossed modules and simplicial groups, and also some functions for
handling simplicial complexes, cubical complexes and regular
CW-complexes in the context of topological data analysis.