$width: 5em
$foo: $bar + $baz
$bar: #{$baz}

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

[
	["variable-line", [
		["variable", "$width"],
		["punctuation", ":"],
		" 5em"
	]],
	["variable-line", [
		["variable", "$foo"],
		["punctuation", ":"],
		["variable", "$bar"],
		["operator", "+"],
		["variable", "$baz"]
	]],
	["variable-line", [
		["variable", "$bar"],
		["punctuation", ":"],
		["variable", "#{$baz}"]
	]]
]

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

Checks for variable declarations.