Category pages (and possibly other specials) #51
Description
Mediawiki, blogging engines, and other similar content management systems have the concept of categories (PReS did). To implement 'special' pages like category pages, we have to create some syntactic construct which will sit comfortably in Markdown, but which we can intepret specially.
We already interpret text enclosed in two square brackets as special - 'local links'. If we adopted a convention that a local link which starts with a colon (i.e. [[:) is a 'special' which can be intepretted specially either when emitting HTML or when the link is past to /wiki, then links starting [[:Category could be the first of the specials, and automatically create category pages.
When an edited page is saved, it is scanned for any such [[:Category links, and the appropriate category pages are automatically updated. Or else, when you browse to a Category page, it is automatically constructed on the fly by grepping for files with such links in them.