How might I get a minimal anchor?

[jidanni]

How might I get a minimal anchor, just out of curiosity?

$ echo '<a id="w"></a>'|
  pandoc --from=html --to=markdown|pandoc
<p><span id="w"></span></p>

OK, I suppose I'll just have to insert a raw

<a id="w"></a>

into the markdown, else whatever markdown I use will end up turning into bigger HTML.

[latent-9]

Pandoc does this because its internal document model has no bare-anchor node. When it reads <a id="w"></a>, the only thing it can represent is an inline with an id and no other content, which is a Span: Span ("w",[],[]) []. On the way out, an inline has to live inside a block, so it gets wrapped in a paragraph, which is why you get <p><span id="w"></span></p>.

There is no markdown or AST construct that maps back to a lone <a id="...">, so keeping it verbatim as raw HTML is exactly the right move, not just a fallback. As long as the raw_html extension is on (it is by default for the html reader and the markdown writer), pandoc stores the tag as a RawInline "html" and passes it through unchanged instead of normalizing it to a span.

So relying on raw_html and leaving the <a id="w"></a> raw is the minimal anchor. There is no smaller pandoc-native representation of it.