Having trouble compiling yesod route after introducing a parameter

Question

I am running a modified example of http://www.yesodweb.com/book/blog-example-advanced

that previously did not use a parameter id of type DBEntitySchemaId. Since introducing it, I am getting

Handler/Entity.hs:146:34:
    Couldn't match type ‘DBEntitySchemaId -> Route App’
                  with ‘Route (HandlerSite (WidgetT App IO))’
    Expected type: WidgetT
                    App IO ((DBEntitySchemaId -> Route App) -> [(Text, Text)] -> Text)
     Actual type: WidgetT
                    App
                    IO
                    (Route (HandlerSite (WidgetT App IO)) -> [(Text, Text)] -> Text)
   In the first argument of ‘(>>=)’, namely ‘getUrlRenderParams’
   In a stmt of a 'do' block:
     (getUrlRenderParams
      >>=
        (\ urender_akdM
           -> (asWidgetT GHC.Base.. toWidget)
                (toHtml (\ u_akdN -> urender_akdM u_akdN [] EntityR))))

which refers to the line using the defaultLayout. The relevant code is:

getEntityR :: DBEntitySchemaId -> Handler Html
getEntityR id = do
  oldEntities <- runDB $ selectList [DBEntityDbentitySchemaId ==. id] []
  fields <- runDB $ selectList [DBFieldDbentitySchemaId ==. id, DBFieldFieldTypeId ==. (toSqlKey 1)] []
  mauthId <- maybeAuthId
  ((res, widget), enctype) <- runFormPost (form fields)
  case (mauthId,res) of
    (Just userId, FormSuccess (attributeValues)) -> do
      setMessageI $ MsgSubmittedKarma
      let entity = DBEntity "Test" id
      entId <- runDB $ insert entity
      let fieldsNVals = zip fields attributeValues
      let einfuegen field attributeValue = case (field, attributeValue) of
                                      ((Entity fldId _), (FormSuccess val)) -> do
                                         a <- runDB $ insert (Attribute {attributeEntityId = entId, attributeDbfieldId = fldId, attributeStringValue =  val})
                                         return (Just a)
                                      _ -> return Nothing
      _ <- forM fieldsNVals (\(field, attributeValue) -> einfuegen field attributeValue)

      redirect $ (EntityR id)
    _ -> do        
      --render <- getUrlRenderParams
      --return $ renderHtml $ [hamlet|
      defaultLayout [whamlet|
          $if null oldEntities
              <p>There are no entities
          $else
              <ul>
                  $forall Entity entityId entity  <- oldEntities
                      <li>
                          <p>#{dBEntityName entity}
          $if mauthId == Nothing
              <form method=post action=@{EntityR} enctype=#{enctype}>
                  <input type=submit value=_{MsgPleaseLogin}>
          $else
              <form method=post action=@{EntityR} enctype=#{enctype}>
                  ^{widget}
                  <input type=submit>
      |]

What I already tried was changing whamlet to hamlet and adding some lines of code from here (commented out)

Trying to send an email in yesod using hamlet

and changing

[whamlet| 

to

[whamlet|@{getEntityR}/#{id}|

and

[whamlet||@?{urlParams id}|

and some variations of this inspired by

Render url with query parameters https://groups.google.com/forum/#!topic/yesodweb/q1gtkOgM32I

I assume there is only a small modification to make. However my understanding of whamlet/hamlet is not too great. So I am posting this in case it is a trivial problem. I fully understand that I need to put in more work, I am just having trouble googling my problem. So please bear with me.

Answer 1

After modifying your route you forgot to pass newly added parameter into @{EntityR} interpolation, something like this: @{EntityR param}.