{msg desc=""}
{msg desc="Foo \"bar\" 'baz'"}
{$foo['bar\'baz\"\"\'']}
{{msg desc="Example: The set of prime numbers is {2, 3, 5, 7, 11, 13, ...}."}}

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

[
	["soy", [
		["delimiter", "{"],
		["keyword", "msg"],
		["property", "desc"],
		["operator", "="],
		["string", "\"\""],
		["delimiter", "}"]
	]],
	["soy", [
		["delimiter", "{"],
		["keyword", "msg"],
		["property", "desc"],
		["operator", "="],
		["string", "\"Foo \\\"bar\\\" 'baz'\""],
		["delimiter", "}"]
	]],
	["soy", [
		["delimiter", "{"],
		["variable", [
			"$foo",
			["punctuation", "["],
			["string", "'bar\\'baz\\\"\\\"\\''"],
			["punctuation", "]"]
		]],
		["delimiter", "}"]
	]],
	["soy", [
		["delimiter", "{{"],
		["keyword", "msg"],
		["property", "desc"],
		["operator", "="],
		["string", "\"Example: The set of prime numbers is {2, 3, 5, 7, 11, 13, ...}.\""],
		["delimiter", "}}"]
	]]
]

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

Checks for strings.