The `reverse()` function returns the input argument in reverse order.

Returns a reversed copy of the input string if the given input value
argument is a string.

Returns a reversed copy of the input array if the given input value
argument is an array.

Returns `null` if the input argument is neither a string nor an array.

-- Testcase --
{%
	printf("%.J\n", [
		reverse("abc"),
		reverse([1, 2, 3]),
		reverse(true)
	]);
%}
-- End --

-- Expect stdout --
[
	"cba",
	[
		3,
		2,
		1
	],
	null
]
-- End --