# Return all prefixes currently in force.
	#
	# The default prefix, if in force, is *not*
	# returned, and will have to be checked for separately.
	#
	# SEE: `NamespaceSupport.prefixes`
	fun prefixes: Collection[String] do
		if prefix_table == null then
			return empty
		else
			return prefix_table.keys
		end
	end