You may want to mention use of LUA more explicitly, just so people know that's how things are getting done. Not all exotic or non-standard uses will use LUA.

Done!

In fact, let's make a Lua in Templates article. There's a lot to talk about there.

Looking forward to see some examples.

It is not related to this mediawiki module: https://www.mediawiki.org/wiki/Extension:Lua

Or is it?

It is not related. Instead of mw:Extension:Lua, Wikia uses a modified version of mw:Extension:Scribunto.

Yes, they are mostly listed in the mw:Extension:Scribunto and Extension:Scribunto/Lua_reference_manual.

The most prominent limitations (that I can remember) include:

• 10 second execution limit  for all lua in a page. 

• 100 modules can be invoked by other modules, at most

• Less than 20 locales can be used in mw.language library ([1])
• Mw language library doesn't support all existing languages.

• Lua is not fully implemented by MediaWiki, a couple of functions have been removed for security purposes.

• Modules cannot access content from other modules within the same page.

Note: The mw library was created by WIkimedia, so those limitations are not related to lua, but the implementation of the library itself.

Okay is sounds like a majority of Lua functionality is supported within those limits. Pretty impressive and a little scary. Then again, some wiki infoboxes are very scary.

Also, there are some functions missing from Wikia's version of Scribunto. Namely:

• /doc in Module:
  • frame:callParserFunction
  • frame:extensionTag
  • frame:getTitle
  • frame:newChild
• As of July 2015, the whole frame library is unavailable in the debug console in wikia's version of Wikipedia:Scribunto. Unlike MediaWiki's version (1.25+) of mw.getCurrentFrame() Wikia's scribunto will return "nil" when used in the debug console.
• 4.8.6.1 File metadata
• 4.8.6.2 Expensive properties

Looks like the line I added to dev.wikia's reference manual. But yes, those are missing, it is particularly annoying that frame:getTitle, and newchild are missing (esp. getCurrentFrame in console).

It is strange though, some of these seem to have been implemented before wikia forked their scribunto version. Maybe there were underlying differences in Mw 1.19 that made it difficult.

Anyway, we've gone slightly off-topic, although the content added here could potentially land in a page of some sort, so it isn't a particularly big problem.