新手小白,请教一个发布org的配置问题

我想配置在org发布的时候,可以发布当前项目的目录,所以base-directory设置为函数ffip-get-project-root-directory返回的项目目录,publishing-directory设置为项目目录加上"html",但是现在发布的时候报错: Wrong type argument: stringp, (ffip-get-project-root-directory) ,请问各位大神,我应该怎么设置?

配置内容如下:

(setq org-publish-project-alist
      '(
        ("org-notes"
         :base-directory (ffip-get-project-root-directory)
         :base-extension "org"
         :publishing-directory (format "%s%s" (ffip-get-project-root-directory) "html")
         :recursive t
         :publishing-function org-html-publish-to-html
         :headline-levels 4             ; Just the default for this project.
         :auto-preamble t
         :auto-sitemap t                ; Generate sitemap.org automagically...
         :sitemap-filename "index.org"  ; ... call it sitemap.org (it's the default)...
         :sitemap-title "笔记列表"         ; ... with title 'Sitemap'.
         )
        ("org-static"
         :base-directory "~/org/"
         :base-extension "css\\|js\\|png\\|jpg\\|gif\\|pdf\\|mp3\\|ogg\\|swf"
         :publishing-directory "~/public_html/"
         :recursive t
         :publishing-function org-publish-attachment
         )
        ("org" :components ("org-notes" "org-static"))
        )
      )

你需要用backquote,看下面这个帖子: