Use guards instead of if

hsilop.hs

@@ -18,7 +18,8 @@ io f = interact (unlines . map f . filter (not . null) . lines)
 result :: Either String Double -> String
 result (Left err) = "Ꞥ∘ " ++ err
 result (Right x)  = printf ("ꟼ∘ " ++ format) x where
-  format = if ceiling x == floor x then "%.0f" else "%.10f"
+  format | ceiling x == floor x = "%.0f"
+         | otherwise            = "%.10f"
 
 
 -- Solve a RPN expression
@@ -28,7 +29,7 @@ rpn = foldM parse [] . words >=> return . head where
   parse (x:xs)   (flip lookup monad -> Just f) = Right (f x : xs)
   parse xs       (flip lookup nilad -> Just k) = Right (k : xs)
   parse xs       (readMaybe -> Just x) = Right (x : xs)
-  parse xs       _                     = Left "syntax error"
+  parse _        _                     = Left "syntax error"
 
 
 -- dyadic functions