**Packages**- unix
- containers
- base
- package

The union function returns the list union of the two lists. For example,
> "dog" `union` "cow" == "dogcw"
Duplicates, and elements of the first list, are removed from the the second list, but if the first list contains duplicates, so will the result. It is a special case of unionBy, which allows the programmer to supply their own equality test.

The Union/Find algorithm implements these operations in (effectively) constant-time:
* Check whether two elements are in the same equivalence class.
* Create a union of two equivalence classes.
* Look up the descriptor of the equivalence class.
Version 0.2

ST based implementation of Tarjan's disjoint set forests, using mutable arrays storing indices instead of references internally. There is also a pure, immutable version of the data structure, which is useful for querying the result of a union find construction.
Version 0.1

A unioning file-system using HFuse
Version 0.0.2