I've never used it, but there is a lattice package on hackage which provides typeclasses for semilattices: http://hackage.haskell.org/package/lattices-1.2.1/do

I've never used it, but there is a lattice package on hackage which provides typeclasses for semilattices: http://hackage.haskell.org/package/lattices-1.2.1/docs/Algebra-Lattice.html http://hackage.haskell.org/package/lattices-1.2.1/docs/Algeb...