See [InterWikiSoftware:WikiWindow] for more discussion; the following is excerpted from there.
Let's say that you want to view the page MeatBall:SandBox through OddMuse. Let's say there was an OddMuse MeatballWiki window set up at http://interwiki.sourceforge.net/cgi-bin/mbOddMuse.cgi. You point your browser at the page http://interwiki.sourceforge.net/cgi-bin/mbOddMuse.cgi?SandBox.
Finally, mbOddMuse.cgi acts as if it got the page from its own PageDatabase, and displays it to you.
The flow of data is:
You can edit the page through the OddMuse window, too. It works similarly.
Hmm, I guess you could say that a wiki window is just a TransClusion with no content of it's own. Note that this is a TransClusion in which you can edit the source, though; people using the window are acting as MeatballWiki community members, rather than members of a different community which has transcluded some pages.
Right now I intend to bypass the markup conversion problem by just having the "real" wiki do the rendering of wiki markup into HTML rather than the frontend wiki; i.e. a UseMod frontend would be have &WikiToHTML? replaced with a call to a WikiGateway.
Eventually I want to add markup conversion routines to WikiGateway; i.e. you would do
$usemodPage = WikiGateway:MoinMoinToUseMod($moinMoinPage), etc. This is a WorseIsBetter approach as compared to waiting for a WikiMarkupStandard.