Playground

import System;

Kind(any? x) : str => x switch
{
	null => "null",
	i32 n => "i32 " + n,
	str s => "text " + s,
	List<i32> l => "a list of " + l.Count,
	_ => "something else",
};

Main()
{
	Console.WriteLine(Kind(null));
	Console.WriteLine(Kind(4));
	Console.WriteLine(Kind("hi"));
	Console.WriteLine(Kind(new List<i32>()));
	Console.WriteLine(Kind(2.5));

	str? maybe = "x";
	if (maybe is str text)
		Console.WriteLine(text.Length);
	if (maybe is not null)
		Console.WriteLine("has a value");
}