Compatibility with yesod-core 1.6

Caveat: I'm not sure that the Semigroup instance is compatible with GHC
before 8.4.

stack.yaml

@@ -4,7 +4,7 @@ packages:
 - 'blaze-colonnade'
 - 'lucid-colonnade'
 - 'siphon'
-# - 'yesod-colonnade'
+- 'yesod-colonnade'
 # - 'geolite-csv'
 # Dependency packages to be pulled from upstream that are not in the resolver
 # (e.g., acme-missiles-0.3)

yesod-colonnade/src/Yesod/Colonnade.hs

@@ -22,10 +22,11 @@ module Yesod.Colonnade
   ) where
 
 import Yesod.Core
-import Yesod.Core.Types (Body(..),GWData(..),WidgetT(..))
+import Yesod.Core.Types (Body(..),GWData(..),WidgetFor(..),wdRef)
 import Colonnade (Colonnade,Headed,Headless)
 import Data.Text (Text)
 import Control.Monad
+import Data.IORef (modifyIORef')
 import Data.Monoid
 import Data.String (IsString(..))
 import Text.Blaze (Attribute,toValue)
@@ -47,9 +48,11 @@ data Cell site = Cell
 instance IsString (Cell site) where
   fromString = stringCell
 
+instance Semigroup (Cell site) where
+  Cell a1 c1 <> Cell a2 c2 = Cell (mappend a1 a2) (mappend c1 c2)
 instance Monoid (Cell site) where
   mempty = Cell mempty mempty
-  mappend (Cell a1 c1) (Cell a2 c2) = Cell (mappend a1 a2) (mappend c1 c2)
+  mappend = (<>)
 
 -- | Create a 'Cell' from a 'Widget'
 cell :: WidgetT site IO () -> Cell site
@@ -189,12 +192,14 @@ li_ = liftParent H.li
 a_ = liftParent H.a
 
 liftParent :: (Html -> Html) -> Attribute -> WidgetT site IO a -> WidgetT site IO a
-liftParent el attrs (WidgetT f) = WidgetT $ \hdata -> do
-  (a,gwd) <- f hdata
-  let Body bodyFunc = gwdBody gwd
-      newBodyFunc render =
-        el H.! attrs $ (bodyFunc render)
-  return (a,gwd { gwdBody = Body newBodyFunc })
+liftParent el attrs (WidgetFor f) = WidgetFor $ \hdata -> do
+  a <- f hdata
+  modifyIORef' (wdRef hdata) $ \gwd ->
+    let Body bodyFunc = gwdBody gwd
+        newBodyFunc render =
+          el H.! attrs $ (bodyFunc render)
+     in gwd { gwdBody = Body newBodyFunc }
+  return a
 
 
 

yesod-colonnade/yesod-colonnade.cabal

@@ -17,11 +17,11 @@ library
   exposed-modules:
     Yesod.Colonnade
   build-depends:
-      base >= 4.9 && < 4.11
+      base >= 4.9 && < 4.12
     , colonnade >= 1.2 && < 1.3
-    , yesod-core >= 1.4 && < 1.5
-    , conduit >= 1.2 && < 1.3
-    , conduit-extra >= 1.2 && < 1.3
+    , yesod-core >= 1.6 && < 1.7
+    , conduit >= 1.3 && < 1.4
+    , conduit-extra >= 1.3 && < 1.4
     , text >= 1.0 && < 1.3
     , blaze-markup >= 0.7 && < 0.9
     , blaze-html >= 0.8 && < 0.10