functional programming - How to create an instance of typeclass Monad[F[_]] of a custom type constructor in Scala Cats -

how can create instance of custom type constructor in cats? know cats comes scala built-in type constructors , can import them e.g import cats.data._ import cats.implicits._ import cats.instances._ know how can create own implicit instance work monads operators sintaxs >>= own custom type constructor. suppose have mytype[a] monadic o @ least has flatmap , pure constructor, want things like:

monad[mytype].pure(x) >>= { _.foobar } 

i saw @ sources of instances package @ examples option seems lot do, don't know if there easy way.

regards.

just provide implicit instance of monad type, , implement required methods:

implicit object mymonad extends monad[mytype] {   def pure[a](x: a): mytype[a] = ???   def flatmap[a, b](fa: mytype[a])(f: => mytype[b]): mytype[b] = ???   def tailrecm[a, b](a: a)(f: => mytype[either[a, b]]): mytype[b] = ??? } 

if confident monad stack-safe, can skip implementing tailrecm , extend stacksafemonad[mytype] instead.