union is:package

package union
Uses
Extensible type-safe unions Extensible type-safe unions for Haskell with prisms using modern GHC features. Dual to vinyl records. Unions are also known as corecords or polymorphic variants. Neither requires a Typeable constraint nor uses unsafe coercions at the cost of linear time access (negligible in practice).
package union-color
Uses
Unify verious color formats Please see the README on GitHub at https://github.com/YoshikuniJujo/union-color#readme
package unionmount
Uses
Not on Stackage, so not searched. Union mount filesystem paths into Haskell datastructures
package union-angle
Uses
Union type that include radian angle and degree angle Please see the README on GitHub at https://github.com/YoshikuniJujo/union-angle#readme
package union-find
Uses
Not on Stackage, so not searched. Efficient union and equivalence testing of sets.
package union-find-array
Uses
union find data structure 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.
package union-map
Uses
Not on Stackage, so not searched. Heterogeneous map by open unions.
package open-union
Uses
Not on Stackage, so not searched. Extensible, type-safe unions.
package clean-unions
Uses
Not on Stackage, so not searched. Open unions without need for Typeable
package funion
Uses
Not on Stackage, so not searched. A unioning file-system using HFuse
package yaml-union
Uses
Not on Stackage, so not searched. Read multiple yaml-files and override fields recursively