Can't get out of recursive in reflex-dom

110 views Asked by At

The code compiles but when run gets stuck in infinite recursive loop. It's not obvious where the loop enters, especially when using recursive do or monadfix. When trying to debug in the browser it finds cyclic evaluation in fixIO at rts.js line 6086

{-# LANGUAGE OverloadedStrings   #-}
{-# LANGUAGE RecursiveDo         #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE MonoLocalBinds      #-}

import Reflex.Dom
import qualified Data.Text as T

main :: IO ()
main = mainWidget game

game :: MonadWidget t m => m ()
game = elClass "div" "game" $ do
  elClass "div" "game-board" $ do
    rec
      stateEv <- board stateEv [["","",""],["","",""],["","",""]]
    elClass "div" "game-info" $ do
      elClass "div" "statu" $ blank
      elClass "ol" "todo" $ blank

board :: MonadWidget t m
      => [[Event t T.Text]]
      -> [[T.Text]]
      -> m [[(Event t T.Text)]]
board s iss = elClass "div" "board" $ do
  el "div" $ do
    elClass "div" "status" $ text "Next player: X"
    mapM (boardRow s) iss

boardRow :: MonadWidget t m
         => [[Event t T.Text]]
         -> [T.Text]
         -> m [(Event t T.Text)]
boardRow s is = elClass "div" "board-row" $ mapM (square s) is

square :: (
            PostBuild t m
          , DomBuilder t m
          , MonadHold t m
          )
       => [[Event t T.Text]]
       -> T.Text
       -> m (Event t T.Text)
square stateEv i = do
  rec
    let ev = domEvent Click e
        ev' = updated dyn
        ev'' = tagPromptlyDyn dyn ev
        dyn = tooglePlayer <$> dynBool

    dyns <- mapM (holdDyn i) (concat stateEv)
    dynBool <- toggle True $ updated $ distributeListOverDyn dyns

    (e, _) <- elAttr' "button" ("type" =: "button" <> "class" =: "square") $ dynText dyn
  return ev''

tooglePlayer :: Bool -> T.Text
tooglePlayer True  = "X"
tooglePlayer False = "O"
0

There are 0 answers