Greetings, I'm trying to write a custom Yesod field for displaying a list of words. I copied the code from textareaField and played with it. Unfortunately, I'm getting a rather strange error message from the compiler. What's I'm doing wrong? data GenTask = GenTask { gtWords :: [String], gtNumResults :: Int } blank :: (Monad m, RenderMessage master FormMessage) => (Text -> Either FormMessage a) -> [Text] -> m (Either (SomeMessage master) (Maybe a)) blank _ [] = return $ Right Nothing blank _ ("":_) = return $ Right Nothing blank f (x:_) = return $ either (Left . SomeMessage) (Right . Just) $ f x textListField = Field { fieldParse = blank $ Right . map T.unpack . T.words , fieldView = \theId name theClass val isReq -> addHamlet [hamlet|\ <textarea id="#{theId}" name="#{name}" :not (null theClass):class="#{T.intercalate " " theClass}" type="text" :isReq:required=""> #{either id (T.pack . unwords) val} |] } gtAForm = GenTask <$> areq textListField "List of words" Nothing <*> areq intField "Number of results to show" (Just 10) [1 of 1] Compiling Main ( src/Web.hs, interpreted ) src/Web.hs:42:9: Exception when trying to run compile-time code: "\ <textarea id="#{theId}" name="#{name}" :not (null theClass):class="#{T.intercalate " " theClass}" type="text" :isReq:required=""> #{either id (T.pack . unwords) val} " (line 2, column 143): unexpected "(" expecting "}" Code: Language.Haskell.TH.Quote.quoteExp hamlet "\\\n<textarea id=\"#{theId}\" name=\"#{name}\" :not (null theClass):class=\"#{T.intercalate \" \" theClass}\" type=\"text\" :isReq:required=\"\"> #{either id (T.pack . unwords) val}\n" Failed, modules loaded: none.