wiki type auto toc (table of content)

hi. i'm looking for a module or a snippet which could be able to generate a toc block given a certain page and ist header structure: h1, h2, etc. like mediawiki, for example (eventually inside the page itself, better if inside a separate block). is anything like this already available? will it be compatible with markdown markup? if not, do you have any ideas on how to start developing something like this (for example starting from existing code one can find in a wiki)? thanks in advance.