Enrico Weigelt wrote:
So I'm planning to extend the common wiki syntax by some additional elements, i.e. some block/section tags (as used by some template engines).
It's worth noting that there isn't really such a thing as "the common wiki syntax" - the variant used by the MediaWiki software has some things in common with the original WikiWiki (via its ancestry as a modified UseMod script), but has gradually evolved to more closely fit the needs of the project(s): magic language links, 'built-in' LaTeX, tables, images, etc. Other wiki engines have similarly evolved to suit their own circumstances - I came upon one wiki devoted to the game of Go, which unsurprisingly has quite elegant syntax for describing Go boards and games, which are then rendered graphically. And some have chosen a completely different "style" for their syntax - using *bold* instead of '''bold''' for instance.
You might want to read around on some of the existing ideas related to this; some of the pages on MeatBall might be a good starting point, such as: http://www.usemod.com/cgi-bin/mb.pl?WikiSyntax http://www.usemod.com/cgi-bin/mb.pl?WikiMarkupStandard
The traditional wiki syntax would in fact be a subset of the new (extendet) syntax. We could now store also some metadata, i.e. changelog, editor-flags (i.e. for non-public areas), etc.
I think it's probably better to think of this not so much as an "extension" to the "traditional" syntax (which essentially doesn't exist), but rather as another syntax that shares similarities with that of MediaWiki (if that is the software you choose to integrate it with / base it on). In other words, go forward and implement a solution to your own needs, and if as a result you produce something that can be 'transparently' included in MediaWiki (without need to drastically reformat existing content, for instance) then all the better.
Happy hacking!