@sghoweri's Twig engine is merged to pattern-engines, with some tweaks and simple unit tests. @EvanLovely has also expressed interest in the Twig engine; Evan, would you be willing to give it a whirl and see what issues come up?

We're not doing anything currently (that I know of) to catch the JSON context directives in Twig template includes, such as with and only. I believe @sghoweri knows about this issue in more detail. Or was that the kind of thing that expandPartials: true solved?