Increment count in low_replace regex

Question

I'm using Low Replace to allow users to add footnotes to the content of their entries. Anything wrapped in square brackets (like this: [[This would become a footnote.]]) will then be replaced with the appropriate markup on the front-end. Here is the code thus far:

{exp:low_replace find="SPACE\[\[(.*?)\]\]" replace="<span class=QUOTEfootnote-numberQUOTE>&sup1;</span><span class=QUOTEfootnoteQUOTE><span class=QUOTEfootnote-numberQUOTE>&sup1;</span> $1</span>" regex="yes"}
    {blog_post_content}
{/exp:low_replace}

There will often be multiple footnotes for one entry, so I need to be able to increment that ¹ with each footnote that's found. So, for example, if there were three footnotes they would be marked-up like this:

<span class="footnote"><span class="footnote-number">&sup1;</span> Footnote content…</span>
<span class="footnote"><span class="footnote-number">&sup2;</span> Footnote content…</span>
<span class="footnote"><span class="footnote-number">&sup3;</span> Footnote content…</span>

How can I increment that number with each footnote?

Answer 1

If you could include the footnote number in the note itself, I think that'd be available via back reference in the Low Replace tag.

So, if your footnotes were like this:

[[This is a footnote.#1]]
[[This is another footnote.#2]]

Then, I think you could do this in your Low Replace tag:

{exp:low_replace find="SPACE\[\[(.*?)(\#\d+)\]\]" replace="<span class=QUOTEfootnote-numberQUOTE>&sup$2;</span><span class=QUOTEfootnoteQUOTE><span class=QUOTEfootnote-numberQUOTE>&sup$2;</span> $1</span>" regex="yes"}
    {blog_post_content}
{/exp:low_replace}

But, if changing your footnote authoring style isn't possible / practical, I think you'd have to "post process" your footnote HTML to count notes, and insert the right count per note.