arianvp

import Control.Monad.IO.Class
import Control.Monad.Codensity
import System.IO


managedActions :: Codensity IO ()
managedActions = do
  input <- Codensity $ withFile "in.txt" ReadMode
  output <- Codensity $ withFile "out.txt" WriteMode
  contents <- liftIO $ hGetContents input

marcosh

module Application where

import Data.Profunctor

newtype Application request response =  Application {unApplication :: request -> IO response}

instance Profunctor Application where
    dimap actOnRequest actOnResponse application = Application $ (fmap actOnResponse) . (unApplication application) . actOnRequest

gelisam

-- Combining Maps using the Applicative idiom.
{-# LANGUAGE DeriveFunctor, DeriveFoldable, DeriveTraversable #-}
module ApplicativeMap where

import Data.Map.Strict (Map)
import qualified Data.Map as Map

-- When combining multiple Applicative computations, a common Haskell idiom is
-- to use (<$>) and (<*>) to combine the results using a function:

carymrobbins

import System.IO.Unsafe

main :: IO ()
main = do
  thing 1
  thing 2
  thing 3

  thing' 1
  thing' 2

adamwespiser

{- stack --resolver lts-16.8 --install-ghc exec ghci --package "protolude text binary" -}
{-# LANGUAGE DeriveGeneric, DuplicateRecordFields, ExistentialQuantification, FlexibleContexts, RankNTypes, ScopedTypeVariables, StandaloneDeriving #-}
{- ghcid -c "stack X.hs" -}

module Existenial where

import Data.Text
import Data.Binary
import GHC.Generics

dagit

{- cabal:
   build-depends: base
   build-depends: transformers
   ghc-options: -threaded

-}

import Control.Concurrent (myThreadId, threadDelay, forkOS)
import Control.Monad (forever,  void)
import Control.Monad.IO.Class (liftIO)

gelisam

-- Based on https://gist.github.com/jship/d2237fad40cfb34166d82597735fbacf
--
-- The above example demonstrates how to flatten all the routes in a record of
-- records of routes, in order to bind a long list of top-level 'Link'
-- functions.
--
-- Below, I demonstrate how to instead go from a record of records of routes to
-- a record of records of 'Link's, and how to easily navigate the resulting
-- nested record.
{-# LANGUAGE DataKinds, DeriveGeneric, DerivingStrategies, FlexibleContexts, GADTs, TypeApplications, TypeOperators #-}