develop...63cbeab · reflex

on 63cbeab help sign in

src/Reflex/Dynamic.hs+10

since splitsnapshots

@@ -34,6 +34,7 @@ module Reflex.Dynamic

34 , attachPromptlyDyn

35 , attachPromptlyDynWith

36 , attachPromptlyDynWithMaybe

37+ , improvingMaybe

37 , foldDyn

38 , foldDyn

38 , foldDynM

39 , foldDynM

39 , foldDynMaybe

40 , foldDynMaybe

@@ -84,6 +85,7 @@ import Prelude hiding (mapM, mapM_)

85import Data.Functor.Misc

86import Data.Functor.Misc

86import Reflex.Class

87import Reflex.Class

88+import Reflex.PostBuild.Class

88import Control.Applicative ((<*>))

90import Control.Applicative ((<*>))

89import Control.Monad hiding (forM, forM_, mapM, mapM_)

91import Control.Monad hiding (forM, forM_, mapM, mapM_)

@@ -251,6 +253,14 @@ attachPromptlyDynWithMaybe f d e =

251 These (_, b) a -> f a b -- Both events are firing, so use the newer value

253 These (_, b) a -> f a b -- Both events are firing, so use the newer value

252 That _ -> Nothing -- The tagging event isn't firing, so don't fire

254 That _ -> Nothing -- The tagging event isn't firing, so don't fire

253

255

256+-- | Dynamic Maybe that can only update from Nothing to Just or Just to Just (i.e., cannot revert to Nothing)

257+improvingMaybe :: (MonadHold t m, PostBuild t m) => Dynamic t (Maybe a) -> m (Dynamic t (Maybe a))

258+improvingMaybe a = do

259+ postBuild <- getPostBuild

260+ holdDyn Nothing $ fmapMaybe (fmap Just) $ leftmost [ updated a

261+ , tagPromptlyDyn a postBuild

262+ ]

263+

254--------------------------------------------------------------------------------

264--------------------------------------------------------------------------------

255-- Demux

265-- Demux

256--------------------------------------------------------------------------------

266--------------------------------------------------------------------------------