quotients of random events

1 files changed, 5 insertions, 4 deletions

diff --git a/src/Sequence/Formula.hs b/src/Sequence/Formula.hs
index fc61efb..66672a2 100644
--- a/src/Sequence/Formula.hs
+++ b/src/Sequence/Formula.hs
@@ -1,7 +1,7 @@
 {-# LANGUAGE RecordWildCards, RankNTypes, TypeSynonymInstances, FlexibleInstances, MultiParamTypeClasses, ViewPatterns, TypeFamilies #-}
 
 module Sequence.Formula
-  ( FormulaM, Formula
+  ( FormulaM, Formula, quot'
   , evalFormula
   , val
   , d, z
@@ -9,9 +9,8 @@ module Sequence.Formula
 
 import Control.Lens
 import Data.Data.Lens
-import Data.Data (Data)
-import Data.Typeable (Typeable)
 
+import Control.Monad
 import Control.Monad.Except
 import Control.Monad.Reader
 import Numeric.Probability.Game.Event
@@ -28,7 +27,7 @@ import Data.Maybe
 
 type FormulaM input a = ReaderT input (ExceptT (Question input) EventM) a
 
-type Formula input = Formulam input Int
+type Formula input = FormulaM input Int
 
 data Question input = Question
                       { answer :: Traversal' input (Formula input)
@@ -46,6 +45,8 @@ instance Integral a => Num (FormulaM input a) where
                sum <$> replicateM (fromIntegral n) y
   fromInteger = return . fromInteger
 
+quot' :: Integral a => FormulaM input a -> FormulaM input a -> FormulaM input a
+quot' = liftM2 quot
 
 askQuestion :: MonadIO m => input -> (Question input) -> m input
 askQuestion input q@(Question{..}) = flip (set answer) input . maybe (throwError q) return <$> askQ prompt (join . fmap readMaybe)