Is there a visual modeling language or style for the functional programming paradigm?

Question

UML is a standard aimed at the modeling of software which will be written in OO languages, and goes hand in hand with Java. Still, could it possibly be used to model softwar

Answer 1

We use theorem provers to do formal modelling (with verification), such as Isabelle or Coq. Sometimes we use domain specific languages (e.g. Cryptol) to do the high level design, before deriving the "low level" Haskell implementation.

Often we just use Haskell as the modelling language, and derive the actual implementation via rewriting.

QuickCheck properties also play a part in the design document, along with type and module decompositions.