context

context provides thread-indexed storage around arbitrary context values. The interface supports nesting context values per thread, and at any point, the calling thread may ask for their current context.

Synopsis

{-# LANGUAGE BlockArguments #-}

import qualified Context

data Thing = Thing
  { stuff :: Int
  }

main :: IO ()
main = do
  Context.withEmptyStore \store -> do
    Context.use store Thing { stuff = 1 } do
      Context.use store Thing { stuff = 2 } do
        thing2 <- Context.mine store
        -- ...
      number1 <- Context.mines store stuff

See the Haddocks for more info on the library.