why re-read from init-buf-string in markdown-export?

[cosmicexplorer]

I'm puzzling over some of the code in markdown-export. After running markdown-after-export-hook, if the buffer is modified by any of the hooks or markdown-standalone, it is re-read from that initial state init-buf-string. Why is that? snip here:

      (run-hooks 'markdown-before-export-hook)
      (markdown-standalone output-buffer-name)
      (with-current-buffer output-buffer
        (run-hooks 'markdown-after-export-hook)
        (save-buffer))
      ;; if modified, restore initial buffer
      (when (buffer-modified-p init-buf)
        (erase-buffer)
        (insert init-buf-string)
        (save-buffer)
        (goto-char init-point))

Is there any reason why this is happening? It doesn't seem to affect anything normally, but I'm working on an asynchronous-export feature for fun (#56) and this erases any input the user has entered from the time export begins to the time the process ends.

[jrblevin]

This was mostly added in commit ae0aeb3. I had to look back at the description to refresh my memory (but the motivation wasn't really written down there). The idea is that functions that run with markdown-before-export-hook are preprocessors of a sort that need to modify the raw Markdown source before being sent to the Markdown processor. For example, one might run a script to carry out automatic equation numbering in a mathematical document. We wouldn't want to actually modify the Markdown document for this, rather, just make the changes temporarily before running Markdown.

[cosmicexplorer]

That makes perfect sense. I'll find a way around it for the async thing.