//define and invoke a function
{
	
	fn greeting() {
		return "Hello world";
	}

	assert greeting() == "Hello world", "Function definition failed";
}

//functions within other function argument lists
{
	fn outer(arg: String) {
		return arg == "Hello world";
	}

	fn inner() {
		return "Hello world";
	}

	assert outer(inner()), "Functions within argument lists failed";
}

//first class functions
{
	fn hello() {
		print "Hello world";
	}

	fn identity(x) {
		return x;
	}

	assert identity(hello) == hello, "First class functions failed";
}

//closures
{
	//closures
	fn makeCounter() {
		var counter: Int = 0;
		fn increment() {
			return ++counter;
		}
		return increment;
	}

	var tally: Function = makeCounter();

	tally();
	tally();
	tally();

	assert tally() == 4, "closures failed";
}