Editing on UltraEdit, for use on MediaWiki, it is unformatted text, but can contain the following elements helpful for highlighting:

[[PAGENAME]] or [[PAGENAME|narrative]]
[http://url] or [http://url narrative]
<~A-Z>http://url
<~A-Z>WP:SHORTCUT<~A-Z>
<~A-Z>WT:SHORTCUT<~A-Z>

The complete list of highlighting. It is great difficulty to write a simple syntax highlighting file that'll highlight this.

The minimum to be useful:

[...] ([..] and anything inside it) and
http://... (http:// and ending with any WHITESPACE. , ; [ ] )

Would love if this can be helped!

Can someone help what a basic syntax file to handle some of these, would look like? I'm getting completely headache after the time trying to work it properly. I am sorry to ask, but it's small, I think, and I find it still unable to work out.

Until a better one arrives, I use this. Please improve?
I color /C1 = BLUE, /C2 = BLUE, /C3 = BLUE, /C4 = LIGHT BLUE + UNDERLINE, /C5= LIGHT BLUE, /C6 = BLUE

Thank you!

Following discussion with one of the guys at IDM, we now have a reasonable first stab at MediaWiki syntax marking:
The boldening of =..= is dodgy, since MediaWiki can contain lines with 2 or 3 or more of these in a row, whereas syntax marking expects a clear "one size fits all". But mostly, this seems to work. A problem that needed some attention was the string handling, there is an "unusual character" used to delimit strings, which was used to fix this.