init init_aplusexpr (
		n_expr: nullable AExpr,
		n_op: nullable TPlus,
		n_expr2: nullable AExpr
	)
	do
		_n_expr = n_expr.as(not null)
		n_expr.parent = self
		_n_op = n_op.as(not null)
		n_op.parent = self
		_n_expr2 = n_expr2.as(not null)
		n_expr2.parent = self
	end