The Neither datatype.

A datatype that discards its two arguments

Neither-Data

Neither-Data provides the type Neither. It is a two-argument data type that ignores its arguments completely and has only one constructor. It is a trivial instance of many typeclasses.
This package also provides the neither function, which constructs a Neither from two type-matching objects, discarding them.

Sources

This package is available on Hackage: neither-data on Hackage
This package is available on GitHub: neither-data on GitHub

Documentation

The documentation of this package is available on Hackage here.
The documentation is available on a GitHub pages site here.