null
_
X
AZ
PRISM
FOOBAR_42

class Foo{
	const BAR = 1;
	const baz = 2;
}

Foo::BAR;
Foo::baz;


switch ($i) {
	case NULL:
		break;
	case X:
		break;
}

----------------------------------------------------

[
	["constant", "null"],
	["constant", "_"],
	["constant", "X"],
	["constant", "AZ"],
	["constant", "PRISM"],
	["constant", "FOOBAR_42"],

	["keyword", "class"],
	["class-name-definition", "Foo"],
	["punctuation", "{"],
	["keyword", "const"],
	["constant", "BAR"],
	["operator", "="],
	["number", "1"],
	["punctuation", ";"],
	["keyword", "const"],
	["constant", "baz"],
	["operator", "="],
	["number", "2"],
	["punctuation", ";"],
	["punctuation", "}"],

	["class-name", "Foo"], ["operator", "::"], ["constant", "BAR"], ["punctuation", ";"],
	["class-name", "Foo"], ["operator", "::"], ["constant", "baz"], ["punctuation", ";"],

	["keyword", "switch"],
	["punctuation", "("],
	["variable", "$i"],
	["punctuation", ")"],
	["punctuation", "{"],
	["keyword", "case"],
	["constant", "NULL"],
	["punctuation", ":"],
	["keyword", "break"],
	["punctuation", ";"],
	["keyword", "case"],
	["constant", "X"],
	["punctuation", ":"],
	["keyword", "break"],
	["punctuation", ";"],
	["punctuation", "}"]

]

----------------------------------------------------

Checks for constants.