As many folks have noted, our current templating system works ok for
simple things, but doesn't scale well -- even moderately complex
conditionals or text-munging will quickly turn your template source into
what appears to be line noise.
And we all thought Perl was bad! ;)
There's been talk of Lua as an embedded templating language for a while,
and there's even an extension implementation.
One advantage of Lua over other languages is that its implementation is
optimized for use as an embedded language, and it looks kind of pretty.
An _inherent_ disadvantage is that it's a fairly rarely-used language,
so still requires special learning on potential template programmers' part.
An _implementation_ disadvantage is that it currently is dependent on an
external Lua binary installation -- something that probably won't be
present on third-party installs, meaning Lua templates couldn't be
easily copied to non-Wikimedia wikis.
There are perhaps three primary alternative contenders that don't
involve making up our own scripting language (something I'd dearly like
to avoid):
* PHP
Advantage: Lots of webbish people have some experience with PHP or can
easily find references.
Advantage: we're pretty much guaranteed to have a PHP interpreter
available. :)
Disadvantage: PHP is difficult to lock down for secure execution.
* JavaScript
Advantage: Even more folks have been exposed to JavaScript programming,
including Wikipedia power-users.
Disadvantage: Server-side interpreter not guaranteed to be present. Like
Lua, would either restrict our portability or would require an
interpreter reimplementation. :P
* Python
Advantage: A Python interpreter will be present on most web servers,
though not necessarily all. (Windows-based servers especially.)
Wash: Python is probably better known than Lua, but not as well as PHP
or JS.
Disadvantage: Like PHP, Python is difficult to lock down securely.
Any thoughts? Does anybody happen to have a PHP implementation of a Lua
or JavaScript interpreter? ;)
-- brion