Metadata is good.
Much in the same way that ReST authors can specify metadata that gets converted to HTML meta elements by rst2html, they should be able to use document links as specified in
One way to implement this would be a copy of the meta directive, with an interface something like
:next type=text/html: chapter3.html
:next type=text/plain: chapter3.txt
:previous type=text/html: chapter1.html
:previous type=text/html dir=rev: chapter
:index type=text/html: index.html
producing in the HTML document
<link rel="next" type="text/html" href="chapter3.html" />
<link rel="next" type="text/plain" href="chapter3.txt" />
<link rel="previous" type="text/html" href="chapter1.html" />
<link rev="previous" type="text/html" href="chapter3.html" />
<link rel="index" type=text/html" href="index.html" />
Types could be inferred from the URI by the writer, possibly.
Another possible interface could a new directive for each of the linktypes described in
.. link-next:: chapter3.html
.. link-next:: chapter3.txt
.. link-previous:: chapter1.html
.. link-previous:: chapter3.html
.. link-alternate:: chapter2.pdf
This has the advantage of looking more like some of the other ReST metadata directives and less like a duplication of HTML.
In this case, there should be a mechanism for defining custom linktypes, too.