> You should also understand that a list itself can be a monad.
A list is not a monad — it’s just a container of values, ie. a functor. A monad is a data structure defines a computation in a specific context, and allows composing these in a sequential manner. For example, the Haskell IO monad is a computational context in which you can do input/output, and all of these IO operations are represented using a data structure of the type “IO <return_value>”.
For example, the function “readLine” has the type “IO String”, and represents a computation that reads a line from standard input and returns it as a string. At runtime, evaluating this value will result in the runtime system asking the user for some input, and at compile-time this is represented as the string (that the user enters at runtime) inside the IO monad.
You're probably use to Monads that wrap a single object, like the maybe monad. Monads can wrap multiple objects or anything. This is the case for a list.
A list is not a monad — it’s just a container of values, ie. a functor. A monad is a data structure defines a computation in a specific context, and allows composing these in a sequential manner. For example, the Haskell IO monad is a computational context in which you can do input/output, and all of these IO operations are represented using a data structure of the type “IO <return_value>”.
For example, the function “readLine” has the type “IO String”, and represents a computation that reads a line from standard input and returns it as a string. At runtime, evaluating this value will result in the runtime system asking the user for some input, and at compile-time this is represented as the string (that the user enters at runtime) inside the IO monad.