factor common functions into Utils

1 files changed, 32 insertions, 0 deletions

diff --git a/lib/Utils.hs b/lib/Utils.hs
new file mode 100644
index 0000000..1eb42fc
--- /dev/null
+++ b/lib/Utils.hs
@@ -0,0 +1,32 @@
+module Utils ( binaryToInt
+             , countElem
+             , xor
+             , right
+             , bet
+             , (&+)
+             ) where 
+
+import Data.Char (digitToInt)
+import Control.Monad
+import Data.Either
+
+
+binaryToInt :: String -> Int
+binaryToInt = foldl (\a x -> a * 2 + digitToInt x) 0
+
+countElem :: (Eq a) => a -> [a] -> Int
+countElem c ls = sum $ map (fromEnum . (== c)) ls
+
+xor :: Bool -> Bool -> Bool
+xor a b = (not a && b) || (a && not b)
+
+right :: Either a b -> b
+right (Right b) = b
+right _ = undefined
+
+bet :: Int -> (Int, Int) -> Bool
+bet k (l, u) = k >= l && k <= u
+
+-- combine filter predicates
+(&+) :: (a -> Bool) -> (a -> Bool) -> (a -> Bool)
+(&+) = liftM2 (&&)