I'm trying to use OverloadedLabels with QuasiQuotes from here package. Using plain lenses works but #foo fails with parsing error during compilation. So does field @"foo". Is there a deeper reason this will not work or could it be be a bug in here's interpolated parser?
{-# language DataKinds #-}
{-# language DeriveGeneric #-}
{-# language DerivingStrategies #-}
{-# language OverloadedLabels #-}
{-# language OverloadedStrings #-}
{-# language TypeApplications #-}
{-# language QuasiQuotes #-}
import Control.Lens
import Data.Text (Text)
import qualified Data.Text.IO as T
import Data.Generics.Product
import Data.Generics.Labels
import Data.String.Here
import GHC.Generics (Generic)
data Test = Test
{ name :: Text
} deriving stock (Eq, Show, Generic)
_name :: Lens' Test Text
_name f (Test a) = fmap (\a' -> Test a') (f a)
t :: Test
t = Test "test"
test :: IO ()
test = do
-- ok
T.putStrLn $ t ^. field @"name"
T.putStrLn $ t ^. #name
putStrLn [i|${t ^. _name}|]
-- parse error
putStrLn [i|The name is ${t ^. field @"name"}|]
putStrLn [i|The name is ${t ^. #name}|]
Error for #name:
test.hs:36:12: error:
• Exception when trying to run compile-time code:
Failed to parse interpolated expression in string: The name is ${t ^. #name}
(line 1, column 25):
0
SrcLoc "" 1 6
Parse error in expression: t ^.
CallStack (from HasCallStack):
error, called at src/Data/String/Here/Interpolated.hs:64:33 in here-1.2.13-HU0AD0x0dD36rY9YuL1gwE:Data.String.Here.Interpolated
Code: Language.Haskell.TH.Quote.quoteExp
i "The name is ${t ^. #name}"
• In the quasi-quotation: [i|The name is ${t ^. #name}|]
|
36 | putStrLn [i|The name is ${t ^. #name}|]
|