Output true rationals in mcrl2 builder

src/prism-converter/Tests.hs

@@ -50,10 +50,10 @@ mcrl2BSpec :: Spec
 mcrl2BSpec = describe "mcrl2BSpec" $ do
   it "works for an example" $ do
     let mdp = Mdp 2 2 (V.fromList [Transition 0 0 1 1.0 Nothing, Transition 0 1 1 1.0 Nothing])
-    let res = "des (0 0.5 1,2,2)\n(0,\"0\",1)\n(0,\"1\",1)\n" -- FIXME Rationals
+    let res = "des (0 1/2 1,2,2)\n(0,\"0\",1)\n(0,\"1\",1)\n" -- FIXME Rationals
     (Build.toLazyText (mcrl2B (convertToMcrl mdp)) ^. strict) `shouldBe` res
 
   it "works for another example" $ do
     let mdp = Mdp 2 1 (V.fromList [Transition 0 0 0 0.5 Nothing, Transition 0 0 1 0.5 Nothing])
-    let res = "des (0 0.5 1,1,2)\n(0,\"0\",0 0.5 1)\n"
+    let res = "des (0 1/2 1,1,2)\n(0,\"0\",0 1/2 1)\n"
     (Build.toLazyText (mcrl2B (convertToMcrl mdp)) ^. strict) `shouldBe` res

src/prism-converter/lib/Mdp.hs

@@ -326,5 +326,5 @@ valmariBlocks part =
 
 -- TODO Support partition
 
-mcrl2B :: Mdp Double -> Build.Builder
+mcrl2B :: Mdp Rational -> Build.Builder
 mcrl2B = Mcrl2.mcrl2B . Mcrl2.convertToMcrl

src/prism-converter/lib/Mdp/Mcrl2.hs

@@ -23,6 +23,7 @@ module Mdp.Mcrl2
 
 import           Data.Ord
 import           Control.Arrow                  ((&&&))
+import           Data.Ratio
 
 import           Lens.Micro.Platform
 import           Data.Vector                    ( Vector )
@@ -32,8 +33,6 @@ import           Data.Text                      ( Text )
 import qualified Data.Text                     as T
 import qualified Data.Text.Lazy.Builder        as Build
 import qualified Data.Text.Lazy.Builder.Int    as Build
-import qualified Data.Text.Lazy.Builder.RealFloat
-                                               as Build
 
 import           Mdp.Types
 
@@ -62,7 +61,7 @@ data Mcrl2Transition = Mcrl2Transition
 type Mcrl2Distribution = Vector Mcrl2PropTrans
 
 data Mcrl2PropTrans = Mcrl2PropTrans
-  { mcrl2PropTransProbability :: Double
+  { mcrl2PropTransProbability :: Rational
   , mcrl2PropTransTarget :: Int
   } deriving (Show, Eq)
 
@@ -75,7 +74,7 @@ makeFields ''Mcrl2PropTrans
 -- doesn't correspond to the actual prism model. Maybe we should provide a
 -- uniform initial distribution over all states.
 
-convertToMcrl :: Mdp Double -> Mcrl2Mdp
+convertToMcrl :: Mdp Rational -> Mcrl2Mdp
 convertToMcrl mdp = Mcrl2Mdp (mdp ^. numStates) (convertTransitionsToMcrl (mdp^.transitions)) initDistri
   where
     initDistri = V.fromList $
@@ -83,7 +82,7 @@ convertToMcrl mdp = Mcrl2Mdp (mdp ^. numStates) (convertTransitionsToMcrl (mdp^.
           [0 .. mdp ^. numStates - 1]
 
 
-convertTransitionsToMcrl :: Vector (Transition Double) -> Vector Mcrl2Transition
+convertTransitionsToMcrl :: Vector (Transition Rational) -> Vector Mcrl2Transition
 convertTransitionsToMcrl trans = mkMcrl2Tans <$> partitionVector (view source &&& view choice) sorted
   where
     sorted = V.create $ do
@@ -92,12 +91,12 @@ convertTransitionsToMcrl trans = mkMcrl2Tans <$> partitionVector (view source &&
       return v
 
 
-mkMcrl2Tans :: Vector (Transition Double) -> Mcrl2Transition
+mkMcrl2Tans :: Vector (Transition Rational) -> Mcrl2Transition
 mkMcrl2Tans distri = Mcrl2Transition (h ^. source) (T.pack $ show $ h ^. choice) (mkPropTrans <$> distri)
   where h = V.head distri
 
 
-mkPropTrans :: (Transition Double) -> Mcrl2PropTrans
+mkPropTrans :: (Transition Rational) -> Mcrl2PropTrans
 mkPropTrans t = Mcrl2PropTrans (t ^. probability) (t ^. target)
 
 
@@ -143,7 +142,7 @@ distributionB distri = foldMap (\x -> propTransB x <> " ") (V.init distri)
 
 propTransB :: Mcrl2PropTrans -> Build.Builder
 propTransB t = Build.decimal (t ^. target) <> " "
-  <> Build.formatRealFloat Build.Fixed Nothing (t ^. probability)
+  <> ratioB (t ^. probability)
 
 
 transitionB :: Mcrl2Transition -> Build.Builder
@@ -151,3 +150,7 @@ transitionB t = "(" <> Build.decimal (t ^. source) <> ","
   <> "\"" <> Build.fromText (t ^. label)
   <> "\"," <> distributionB (t ^. outDistribution)
   <> ")\n"
+
+
+ratioB :: Rational -> Build.Builder
+ratioB r = Build.decimal (numerator r) <> "/" <> Build.decimal (denominator r)