Making two widgets on one page in yesod [closed]

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Closed 6 years ago.

I need to add two widgets together in one page like this :

getPageR :: Handler Html
getPageR = defaultLayout $ do
        aDomId <- newIdent
        setTitle "Titre de la page"
    $(widgetFile "rightzone" ++ "leftzone")

but this gives me a error.

Answer 1

I don't use yesod, but a quick Hayoo! suggests that the type of widgetFile is String -> Q Exp. That's a Template Haskell expression. I'm guessing your error is that you can't apply the ++ operator to a Q Exp from widgetFile "rightzone" and a String from "leftzone".

defaultLayout is WidgetT site IO () -> HandlerT site IO Html, so $(widgetFile ...) should be a Template Haskell expression for something of type WidgetT site IO (). So, to combine two widgets, you are probably looking for a function with a type like WidgetT site IO () -> WidgetT site IO () -> WidgetT site IO (). WidgetT has a Monad instance Monad m => Monad (WidgetT site m), so Monad's >> operator should have the right type to combine two widgets together. If your two widgets are "rightzone" and "leftzone", you probably want to do something like $(widgetFile "rightzone") >> $(widgetFile "leftZone"). You can probably write this as

getPageR :: Handler Html
getPageR = defaultLayout $ do
        aDomId <- newIdent
        setTitle "Titre de la page"
        $(widgetFile "rightzone") >> $(widgetFile "leftzone")

or as

getPageR :: Handler Html
getPageR = defaultLayout $ do
        aDomId <- newIdent
        setTitle "Titre de la page"
        $(widgetFile "rightzone")
        $(widgetFile "leftzone")

I have no idea what >> means for widgets, but it should have the right type to be able to try it and find out.