如何将lua-filter与bookdown gitbook输出配合使用？

Question

我有一个示例书项目，带有gitbook输出

index.Rmd：

---
title: "An Example Project"
author: "Coderoo"
output:
  bookdown::gitbook: default
    pandoc_args: ["--lua-filter=hello.lua"]
documentclass: book
---

Some text {{helloworld}}

hello.lua直接从pandoc lua过滤器文档中获取：

return {
  {
    Str = function (elem)
      if elem.text == "{{helloworld}}" then
        return pandoc.Emph {pandoc.Str "Hello, World"}
      else
        return elem
      end
    end,
  }
}

但是当我尝试制作这本书时：

Rscript -e "bookdown::render_book('index.Rmd','bookdown::gitbook')"

我收到此错误：

Error in yaml::yaml.load(..., eval.expr = TRUE) : 
  Scanner error: mapping values are not allowed in this context at line 5, column 16
Calls: <Anonymous> ... parse_yaml_front_matter -> yaml_load -> <Anonymous> -> .Call
Please delete _main.Rmd after you finish debugging the error.
Execution halted

如果我将YAML元数据中的bookdown::gitbook default替换为html_document，那么一切正常。

也交叉发布在这里：https://community.rstudio.com/t/how-to-use-lua-filter-with-gitbook-output/48256

编辑：在rstudio论坛中回答。