Back around 2001 I was part of a webdev shop that had its own proprietary application server. It pre-parsed HTML files for <script language="perl"> or <script l

Back around 2001 I was part of a webdev shop that had its own proprietary application server. It pre-parsed HTML files for <script language="perl"> or <script language="python"> and would run whatever you put there. We linked in slightly patched perl/python libraries so we didn't have to start a new interpreter every request. There were a couple in-house RPN languages too, and other comment-based markup for easy loops/interpolations. One design goal was to let you round-trip between developers' editors and designers' Dreamweaver, so that even after adding code the designers could still see real HTML and usually even change it. I haven't seen any system so successful at that part since. (I love Haml, but design tools don't. :-) Anyway, I got to help out with porting the app server from Solaris to Linux, and one of the tricks they were using was to stuff some extra info into unused areas of the Solaris file struct, basically to smuggle it around without needing to rewrite anything. As long as you could get to the struct, you could retrieve what you put there. It was a brilliant-but-horrifying trick, and of course it was a big challenge for the porting effort.