Knuth created "unofficial" modified versions, such as TeX-XeT, which allows a user to mix texts written in left-to-right and right-to-left writing systems in the same document.
高德纳创建了“非官方”修改版本，例如TeX-XeT，它允许用户在同一文档中混合写入从左到右和从右到左书写系统的文本。