# Write the full line for the element `e` in `o`.
	#
	# Basically it does:
	#
	# ~~~nitish
	# o.write "{prefix}{display(e)}\n"
	# ~~~
	#
	# Usually, you should redefine `display` to change the display of an element.
	protected fun write_line(o: Writer, e: E, prefix: String)
	do
		o.write "{prefix}{display(e)}\n"
	end