Solution: Console.ReadKey() |> ignore Explanation: Console.ReadKey() returns an object of type ‘ConsoleKeyInfo’ but you’re using it as a statement without assigning the return value to anything. So F# warns you that you’re ignoring a value. ignore takes any type and returns nothing. It could be defined like this: let ignore _ = ()
The usual idiom is to define the function to take one argument of type Unit (let functionName () = 42). It will then be called as functionName (). (The unit type has only one value, which is ().)
() is a value of the type () and its purpose is to be useless. Everything in Rust is an expression, and expressions that return “nothing” actually return (). The compiler will give an error if you have a function without a return type but return something other than () anyway. For example fn f() … Read more
tl;dr () does not add a “null” value to every type, hell no; () is a “dull” value in a type of its own: (). Let me step back from the question a moment and address a common source of confusion. A key thing to absorb when learning Haskell is the distinction between its expression … Read more