Footnote anchor link IDs should have a prefix that is deterministic/unique to the article in which it appears, so that in full-body listings of multiple articles the IDs do not collide.

Since the metas of the current article are now visible to tag functions, perhaps the prefix should default to some encoding of ‘here-path’, or if that is not present, some hash of the first string contained in the first element of the document.

MD5 hashes look cooler, but some light testing shows that <code>uri-encode</code> from is faster. Maybe use that on <code>(remove-ext* here-path)</code>.

Here’s a quick way to get just a string out of a txexpr:

<pre><code>(define (tx-strs xpr)
  (cond
    [(txexpr? xpr) (apply string-append (map tx-strs (get-elements xpr)))]
    [(string? xpr) xpr]
    [else