expr : expr LBRACE expr_list RBRACE
            | expr LBRACE RBRACE

def p_cellarrayref(p):
    """expr : expr LBRACE expr_list RBRACE
            | expr LBRACE RBRACE
    """
    args = node.expr_list() if len(p) == 4 else p[3]
    assert isinstance(args, node.expr_list)
    p[0] = node.cellarrayref(func_expr=p[1], args=args)