sohang3112 · August 22, 2024 05:59
diff --git a/html_attributes.hs b/html_attributes.hs
 -- Simple function to handle HTML attributes that may or may not have a value specified.

 import qualified Data.Map as Map
 import Data.Map (Map)

 -- HTML Property Key | Value
 type Prop k v = Either k v

 key = Left
 val = Right

 htmlProps :: Ord k => [Prop k v] -> Maybe (Map k (Maybe v))
 htmlProps = fmap Map.fromList . go
  where go :: [Prop k v] -> Maybe [(k, Maybe v)]
        go [] = Just []
        go [Left k] = Just [(k, Nothing)] 
        go (Left k : rest@(Left _ : _)) = ((k, Nothing) :) <$> go rest
        go (Left k : Right v : rest) = ((k, Just v) :) <$>  go rest
        go (Right _ : _) = Nothing

 -- Example Usage
 -- This prints output: Just (fromList [("class",Just "foo bar baz"),("hidden",Nothing),("id",Just "pass"),("required",Nothing)])
 main = print $ htmlProps [
        key "id", val "pass", 
        key "required", 
        key "hidden", 
        key "class", val "foo bar baz"
      ]
	-- Simple function to handle HTML attributes that may or may not have a value specified.

	import qualified Data.Map as Map
	import Data.Map (Map)

	-- HTML Property Key \| Value
	type Prop k v = Either k v

	key = Left
	val = Right

	htmlProps :: Ord k => [Prop k v] -> Maybe (Map k (Maybe v))
	htmlProps = fmap Map.fromList . go
	where go :: [Prop k v] -> Maybe [(k, Maybe v)]
	go [] = Just []
	go [Left k] = Just [(k, Nothing)]
	go (Left k : rest@(Left _ : _)) = ((k, Nothing) :) <$> go rest
	go (Left k : Right v : rest) = ((k, Just v) :) <$> go rest
	go (Right _ : _) = Nothing

	-- Example Usage
	-- This prints output: Just (fromList [("class",Just "foo bar baz"),("hidden",Nothing),("id",Just "pass"),("required",Nothing)])
	main = print $ htmlProps [
	key "id", val "pass",
	key "required",
	key "hidden",
	key "class", val "foo bar baz"
	]