err0r500

{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE UndecidableInstances #-}

module Main where

import Control.Monad.Identity

data User = User
  { name :: String
  , firstName :: String

err0r500

{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}

module Main where

import Control.Monad.Except
import Control.Monad.Reader
import Control.Monad.State
import Control.Monad.Writer

err0r500

module Main where

import Control.Monad.Identity

-- boostrap the conditions leading to 2 different implementations of the same business logic
main :: IO ()
main = do
  -- use a monad instance as 1st parameter in order to choose the implementation
  expectedCalledWithMaybeInstance <- putStrLn $ getFirstName Nothing "heyhey"
  expectedCalledWithIOInstance <- putStrLn $ getFirstName (Identity 0) "hoho"

err0r500

package main

import (
	"github.com/auth0/go-jwt-middleware"
	"github.com/dgrijalva/jwt-go"
	"gopkg.in/gin-gonic/gin.v1"
)

func main() {
	startServer()