I've generalized this page to be a code conventions portal. Branching off specific languages to other dedicated pages. The "do as PHP unless stated otherwise" is getting old because JavaScript, for instance, is simply very different than PHP. And although the end result in syntax may be similar at times, the reasoning behind is very different. Therefor it's better to describe it in the right context with examples that make sense.
See also the Restructure MediaWiki.org-thread on Project:Current issues.