Expose general behavior as elemOf

byg/src/Function.hs

@@ -7,7 +7,6 @@ module Function
   , fileComponents
   , lowerString
   , elemOf
-  , elemOf'
   , makeTemplate
   , applyTemplate
   , toText
@@ -83,8 +82,7 @@ class (Show w, Lift w) => WitnessFor w t | w -> t, t -> w where
   witnessValue :: w
 
 data StringType = StringType deriving (Show, Lift)
-instance WitnessFor StringType String where
+instance WitnessFor StringType String where witnessValue = StringType
-  witnessValue = StringType
 
 data ElemOf a where ElemOf :: WitnessFor w a => w -> ElemOf a
 deriving instance Show (ElemOf a)
@@ -92,11 +90,8 @@ deriving instance Lift (ElemOf a)
 instance (Show a, Lift a, Valuable a, Eq a) => IsFunction (ElemOf a) (a, [a]) Bool where
   evalFunction (ElemOf _) (y, ys) = y `elem` ys
 
-elemOf :: (Show t, Lift t, Valuable t, Eq t, TokenableTo t a, TokenableTo [t] b, WitnessFor w t) => w -> a -> b -> DepGenM (Token Bool)
+elemOf :: forall t w a b. (Show t, Lift t, Valuable t, Eq t, TokenableTo t a, TokenableTo [t] b, WitnessFor w t) => a -> b -> DepGenM (Token Bool)
-elemOf witness a b = runFunction (ElemOf witness) =<< toTupleToken a b
+elemOf a b = runFunction (ElemOf (witnessValue :: w)) =<< toTupleToken a b
-
-elemOf' :: (Show t, Lift t, Valuable t, Eq t, WitnessFor w t, TokenableTo t a, TokenableTo [t] b) => a -> b -> DepGenM (Token Bool)
-elemOf' = elemOf witnessValue
 
 
 data MakeTemplate = MakeTemplate deriving (Show, Lift)

byg/src/SiteGenerator.hs

@@ -17,7 +17,7 @@ copyTo path targetDir = do
 hasExtension :: (TokenableTo [String] a, TokenableTo FilePath b) => a -> b -> DepGenM (Token Bool)
 hasExtension exts filename = do
   ext <- lowerString =<< untupleSndDepGenM =<< fileComponents filename
-  ext `elemOf'` exts
+  ext `elemOf` exts
 
 handleRecipeDir :: Token FilePath -> Token Template -> Token FilePath -> Token FilePath -> DepGenM ()
 handleRecipeDir outputDir htmlTemplate indexName dir = do