init init_aloopexpr (
		n_kwloop: nullable TKwloop,
		n_block: nullable AExpr,
		n_label: nullable ALabel
	)
	do
		_n_kwloop = n_kwloop.as(not null)
		n_kwloop.parent = self
		_n_block = n_block
		if n_block != null then n_block.parent = self
		_n_label = n_label
		if n_label != null then n_label.parent = self
	end