{-# OPTIONS -fglasgow-exts #-}

{- |

Module : $EmptyHeader$

Description : <optional short description entry>

Copyright : (c) <Authors or Affiliations>

License : GPLv2 or higher, see LICENSE.txt

Maintainer : <email>

Stability : unstable | experimental | provisional | stable | frozen

Portability : portable | non-portable (<reason>)

<optional description>

-}

module ModalCaslToMu where

import Control.Monad as Monad

import Data.Maybe as Maybe

import ModalCasl as Casl

import Mu as Mu

{------------------------------------------------------------------------------}

{- -}

{- Convert Modal CASL formulas to formulas of the �-Calculus -}

{- -}

{------------------------------------------------------------------------------}

convert :: Casl.StateFormula a -> Maybe (Mu.StateFormula a)

convert (Casl.Var x) = Just (Mu.Var x)

convert (Casl.Snot phi) = liftM Mu.Snot (convert phi)

convert (Casl.Sand phi psi) = liftM2 Mu.Sand (convert phi) (convert psi)

convert (Casl.Sor phi psi) = liftM2 Mu.Sor (convert phi) (convert psi)

convert (Casl.E phi) = liftM Mu.E (convert' phi)

convert (Casl.A phi) = liftM Mu.A (convert' phi)

convert (Casl.Diamond phi) = liftM Mu.Diamond (convert phi)

convert (Casl.Box phi) = liftM Mu.Box (convert phi)

convert (Casl.DiamondPast phi) = liftM Mu.DiamondPast (convert phi)

convert (Casl.BoxPast phi) = liftM Mu.BoxPast (convert phi)

convert (Casl.Mu x phi) = liftM (Mu.Mu x) (convert phi)

convert (Casl.Nu x phi) = liftM (Mu.Nu x) (convert phi)

convert' :: Casl.PathFormula a -> Maybe (Mu.PathFormula a)

convert' (Casl.State phi) = liftM Mu.SF (convert phi)

convert' (Casl.Pnot phi) = liftM Mu.Pnot (convert' phi)

convert' (Casl.Pand phi psi) = liftM2 Mu.Pand (convert' phi) (convert' psi)

convert' (Casl.Por phi psi) = liftM2 Mu.Por (convert' phi) (convert' psi)

convert' (Casl.X phi) = liftM Mu.X (convert' phi)

convert' _ = Nothing

{------------------------------------------------------------------------------}