# Set an attribute in the list.
	#
	# For the sake of speed, this method does no checking
	# for name conflicts or well-formedness: such checks are the
	# responsibility of the application.
	#
	# Parameters:
	#
	# * `index`: index of the attribute (zero-based).
	# * `uri`: Namespace URI, or the empty string if
	# none is available or Namespace processing is not being performed.
	# * `local_name`: local name, or the empty string if
	# Namespace processing is not being performed.
	# * `qname`: qualified (prefixed) name, or the empty string
	# if qualified names are not available.
	# * `attribute_type`: attribute type as a string.
	# * `value`: attribute value.
	fun set(index: Int, uri: String, local_name: String, qname: String,
			attribute_type: String, value: String) do
		assert index_in_bounds: index >= 0 and index < length
		data[index * 5] = uri
		data[index * 5 + 1] = local_name
		data[index * 5 + 2] = qname
		data[index * 5 + 3] = attribute_type
		data[index * 5 + 4] = value
	end