able -> DerivDecl -> FunDecl
createFunDecl specDecl v derDecl = Fun fun vars expr Nothing
    where vars = specDecl ^. specArgs
          fun  = specDecl ^. specName
          expr = caseExprFromDerivation v derDecl

caseExprFromDerivation :: Varia
createFunDecl :: SpecDecl -> Variable -> DerivDecl -> FunDecl
createFunDecl specDecl v derDecl = Fun fun vars expr Nothing
    where vars = specDecl ^. specArgs
          fun  = specDecl ^. specName
          expr = caseExprFromDerivation v derDecl
createFunDecl specDecl v derDecl = Fun fun vars expr Nothing
    where vars = specDecl ^. specArgs
          fun  = specDecl ^. specName
          expr = caseExprFromDerivation v derDecl