.. |biohazard| image:: biohazard.png
.. |Red light| image:: red_light.png

.. |Michael| user:: mjones
.. |Jon|     user:: jhl

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

[
	["punctuation", ".."],
	["substitution-def", [
		["substitution", [
			["punctuation", "|"],
			"biohazard",
			["punctuation", "|"]
		]],
		["directive", [
			"image",
			["punctuation", "::"]
		]]
	]],
	" biohazard.png\r\n",

	["punctuation", ".."],
	["substitution-def", [
		["substitution", [
			["punctuation", "|"],
			"Red light",
			["punctuation", "|"]
		]],
		["directive", [
			"image",
			["punctuation", "::"]
		]]
	]],
	" red_light.png\r\n\r\n",

	["punctuation", ".."],
	["substitution-def", [
		["substitution", [
			["punctuation", "|"],
			"Michael",
			["punctuation", "|"]
		]],
		["directive", [
			"user",
			["punctuation", "::"]
		]]
	]],
	" mjones\r\n",

	["punctuation", ".."],
	["substitution-def", [
		["substitution", [
			["punctuation", "|"],
			"Jon",
			["punctuation", "|"]
		]],
		["directive", [
			"user",
			["punctuation", "::"]
		]]
	]],
	" jhl"
]

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

Checks for substitution definitions.