Cubicle 1.1.2 documentation and source : Types.Atom.variables

let rec variables = function
    | True | False -> Variable.Set.empty
    | Comp (t1, _, t2) -> 
       Variable.Set.union (Term.variables t1) (Term.variables t2)
    | Ite (sa, a1, a2) -> 
       let acc = Variable.Set.union (variables a1) (variables a2) in
       Variable.Set.union acc (SAtom.variables sa)